All questions of NCERT Based Tests for UPSC CSE Exam

The Government of India instituted an ‘Amrita Devi Bishnoi National Award for Wildlife Conservation’ in the memory of Amrita Devi Bishnoi, who in 1731 sacrificed her life along with 363 others for the protection of ‘khejri’ trees in Khejarli village near Jodhpur in Rajasthan.

When 6 gram of carbon is 16 gram oxygen bicycle of carbon dioxide is produced if 6 gram of carbon is burn this gram of oxygen then the carbon dioxide used below answer

Introduction:
In the given options, we are asked to identify the natural polymers among cotton, PET, and plastic. To determine this, we need to understand what natural polymers are and how they differ from synthetic polymers.

Natural Polymers:
Natural polymers are large molecules composed of repeating subunits found in nature. These polymers are typically derived from living organisms and can be extracted or synthesized from natural sources. Unlike synthetic polymers, natural polymers have a complex molecular structure and are biodegradable.

Analysis of the Options:
Let's analyze each option to determine if it is a natural polymer:

1. Cotton: Cotton is a natural polymer. It is composed of cellulose, a complex carbohydrate, which is a natural polymer found in the cell walls of plants. Cotton fibers are made up of long chains of cellulose molecules, making it a natural polymer.

2. PET (Polyethylene terephthalate): PET is a synthetic polymer and not a natural polymer. It is a thermoplastic polymer that is derived from petroleum. PET is commonly used in the production of bottles, containers, and polyester fibers.

3. Plastic: The term "plastic" is a broad category that includes both natural and synthetic polymers. However, in the context of the given options, it is unclear which specific type of plastic is being referred to. Some plastics, such as polypropylene and polyethylene, are derived from petroleum and are synthetic polymers. On the other hand, there are certain types of natural polymers, such as natural rubber and shellac, that can be considered as plastics. Without further information, we cannot definitively categorize "plastic" as a natural polymer.

Conclusion:
Based on the analysis, it can be concluded that cotton (option 1) is the only example of a natural polymer among the given options. PET (option 2) is a synthetic polymer, and the categorization of "plastic" (option 3) as a natural polymer is ambiguous without additional information. Therefore, the correct answer is option 'A' - 1 only.

All the Biotic Components in an area together with the abiotic constituents of the environment form an ecosystem. Biotic components comprising living organisms and abiotic components comprising physical factors like temperature, rainfall, wind, soil and minerals

The correct answer is option 'D' - 1, 2 and 3. Let's understand why each statement is correct:

1. It enhances the water holding capacity of the soil:
Organic manure, such as compost or animal manure, contains organic matter that improves the water holding capacity of the soil. When organic matter decomposes, it forms humus, which acts as a sponge, holding water in the soil. This helps to prevent water runoff and allows the soil to retain moisture for a longer period. As a result, the soil becomes more capable of sustaining plant growth, especially during dry periods.

2. It makes the soil loose and porous:
Organic manure contains organic matter that enriches the soil and improves its structure. The organic matter helps to break up compacted soil, making it loose and porous. This improves the soil's ability to hold air and water, facilitating better root growth and nutrient uptake by plants. The increased porosity also enhances soil drainage, preventing waterlogging and reducing the risk of root rot.

3. It enhances the number of friendly microbes:
Organic manure provides a food source for beneficial microorganisms in the soil. These microbes break down organic matter and release essential nutrients in a form that plants can absorb. The presence of organic manure in the soil promotes the growth and multiplication of these beneficial microbes, such as bacteria, fungi, and earthworms. These microbes help in nutrient cycling, soil aeration, and the suppression of harmful pathogens, thus creating a healthier soil ecosystem.

In conclusion, organic manure has several positive effects on soil health. It enhances the water holding capacity of the soil, making it more resilient to drought conditions. It also improves soil structure, making it loose and porous, which aids in root growth and nutrient availability. Additionally, organic manure promotes the growth of friendly microbes that contribute to nutrient cycling and soil health. Therefore, all three statements are correct.

Sahiwal is a breed of 'Zebu cattle' and is considered to be one of the best milch cattle breeds in India. The breed has derived its name from the Sahiwal area in Montgomery district of Punjab in Pakistan.

All the statements are correct.

Introduction:
Nitrogen is an essential nutrient required by plants for their growth and development. It is a major component of proteins, nucleic acids, and chlorophyll. Most plants obtain nitrogen from the soil in the form of nitrates or ammonium ions. However, some crops have the ability to fix atmospheric nitrogen with the help of symbiotic bacteria.

Explanation:
Among the given options, beans (option C) do not require nitrogenous fertilizer. Let's understand why.

Nitrogen Fixation:
Some plants have a symbiotic relationship with nitrogen-fixing bacteria, which are capable of converting atmospheric nitrogen into a usable form for plants. This process is called nitrogen fixation. These bacteria reside in root nodules of leguminous plants, such as beans, peas, and lentils. The bacteria take atmospheric nitrogen and convert it into ammonia, which is then used by the plants for their growth. Therefore, leguminous crops like beans do not require nitrogenous fertilizers as they can obtain nitrogen through biological fixation.

Other Crops:
1. Wheat (option A): Wheat is not capable of nitrogen fixation and relies on the availability of nitrogen in the soil. Therefore, wheat crops require nitrogenous fertilizers to meet their nitrogen requirements.
2. Millet (option B): Similar to wheat, millet crops do not have the ability to fix atmospheric nitrogen. Hence, they need nitrogenous fertilizers to fulfill their nitrogen needs.
3. Paddy (option D): Paddy, also known as rice, does not have the ability to fix nitrogen either. It requires nitrogenous fertilizers to meet its nitrogen demands.

Conclusion:
In conclusion, among the given options, beans do not require nitrogenous fertilizers as they have the ability to fix atmospheric nitrogen with the help of symbiotic bacteria present in their root nodules. On the other hand, crops like wheat, millet, and paddy rely on nitrogenous fertilizers to meet their nitrogen requirements.

Refraction of Sound: Explanation

Introduction:
Sound is a form of energy that travels in the form of waves through different mediums. The speed of sound varies depending on various factors such as temperature, humidity, and wind conditions. One of the phenomena that affect the propagation of sound is refraction.

Definition of Refraction:
Refraction is the bending of sound waves as they pass from one medium to another due to a change in their speed. When sound waves enter a medium with a different density or temperature, they change their direction.

Refraction of Sound in the Atmosphere:
During the day, the temperature of the Earth's surface increases, leading to the heating of the air closest to the surface. This causes the air near the surface to be less dense compared to the higher layers of the atmosphere. As a result, the speed of sound in the lower layers of the atmosphere is lower than the speed of sound in the upper layers.

Explanation:
The phenomenon of refraction causes sound waves to bend towards the region of higher speed as they travel from one medium to another. In the case of sound traveling through the atmosphere, the sound waves tend to bend away from the surface of the Earth during the day.

This bending of sound waves away from the surface of the Earth during the day prevents the sound from reaching longer distances. The sound waves get reflected back towards the ground due to the change in medium and the bending effect. Hence, the sound is heard at shorter distances during the day.

However, during the night, the surface of the Earth cools down, causing the air near the surface to become denser. This leads to a reversal in the density gradient of the atmosphere. As a result, the sound waves tend to bend towards the surface of the Earth during the night.

Implication:
This bending effect allows sound waves to travel longer distances during the night. The sound waves refract towards the ground and follow a curved path, allowing them to reach distant locations. This is why sound is heard at longer distances during the night compared to the day.

Conclusion:
In conclusion, the phenomenon of refraction plays a significant role in the propagation of sound waves. During the day, the bending of sound waves away from the surface of the Earth limits the distance over which the sound can be heard. However, during the night, the bending of sound waves towards the surface of the Earth allows them to travel longer distances, resulting in sound being heard at greater distances.

Rocket Propulsion follow these two principles: 

A physical change involves only change in physical state whereas a chemical change results in the formation of new substances. Boiling of water, melting of ice and dissolution of salt are physical changes as no new products are formed.

Differences between plant and animal cells:

1. Cell wall:
- Statement 1: Animal cells, in contrast to plant cells, do not have a cell wall.
- Explanation: The cell wall is a rigid structure that surrounds the cell membrane in plant cells. It provides support and protection to the cell. Animal cells, on the other hand, do not have a cell wall. Instead, they have a flexible cell membrane that allows for movement and flexibility.

2. Plastids:
- Statement 2: Plastids are found only in plant cells.
- Explanation: Plastids are specialized organelles found in plant cells. They are responsible for various functions, such as photosynthesis, storage of pigment, and synthesis of lipids. Plastids include chloroplasts (responsible for photosynthesis), chromoplasts (store pigments), and leucoplasts (store starch and oils). Animal cells do not possess plastids.

3. Vacuoles:
- Statement 3: Plant cells have one, central vacuole, whereas animal cells have many small vacuoles.
- Explanation: Vacuoles are fluid-filled sacs found in both plant and animal cells, but their size and number differ. Plant cells typically have one large central vacuole that occupies a significant portion of the cell's volume. This central vacuole serves various functions, including storage of water, ions, nutrients, and waste products. In contrast, animal cells have multiple small vacuoles that are scattered throughout the cytoplasm. These vacuoles are involved in diverse functions such as storage, digestion, and excretion.

Conclusion:
- Correct answer: Option C (2 and 3 Only)
- Explanation: The correct statements are 2 and 3. Animal cells lack a cell wall (statement 1 is incorrect). Plastids are exclusive to plant cells (statement 2 is correct). Plant cells have a central vacuole, while animal cells have multiple small vacuoles (statement 3 is correct).

**Explanation:**

When a positive charge moves in a magnetic field, it experiences a force perpendicular to both its velocity and the magnetic field direction. This force is given by the formula:

**F = q(v x B)**

Where:
- **F** is the force experienced by the charge
- **q** is the charge of the particle
- **v** is the velocity of the particle
- **B** is the magnetic field

In this case, the positive charge is moving towards a person, so its velocity is directed towards the person. The force experienced by the charge will be perpendicular to both the velocity and the magnetic field.

If the magnetic field lines were vertically upward or downward, the force experienced by the charge would be in the horizontal direction. This would cause the charge to move in a circular path around the person.

However, if the magnetic field lines were directed in a clockwise or anticlockwise direction, the force experienced by the charge would have a vertical component. This means that the charge would be pushed either upwards or downwards, depending on the direction of the magnetic field.

Since the positive charge is moving towards the person, the force experienced by the charge must be directed away from the person in order to push the charge towards them. This can only happen if the magnetic field lines are directed in the **anticlockwise** direction, as shown in the diagram below:

```
X → O
↑ ↑
| |
| |
↓ ↓
O ← X
```

Here, the X represents the positive charge, the O represents the person, and the arrows represent the direction of the magnetic field lines.

Therefore, the correct answer is option **B) Anticlockwise direction**.

Its an exothermic process.

Explanation:

Statement 1: Calcium hydroxide is also called as quicklime.
- This statement is incorrect. Calcium hydroxide is not the same as quicklime. Quicklime is actually calcium oxide (CaO), which is produced by heating calcium carbonate (lime) at high temperatures.

Statement 2: Calcium hydroxide reacts slowly with the carbon dioxide in air to form a thin layer of calcium carbonate on the walls after two to three days of whitewashing.
- This statement is correct. When calcium hydroxide (also known as slaked lime) is exposed to the carbon dioxide in the air, it reacts to form calcium carbonate. This process, known as carbonation, results in the formation of a thin layer of calcium carbonate on the walls after a few days of whitewashing.

Therefore, the correct answer is option B - 2 Only.

The correct answer is option 'B', the Ramsar Convention.

The Ramsar Convention is an international treaty that was signed in Ramsar, Iran, in 1971. It is officially called the Convention on Wetlands of International Importance, especially as Waterfowl Habitat. This convention is dedicated to the conservation and wise use of wetlands, recognizing their ecological importance and the vital role they play in maintaining biodiversity and providing various ecosystem services.

The Ramsar Convention aims to achieve the following objectives:

1. Conservation: The convention promotes the conservation and wise use of wetlands, recognizing their importance for maintaining ecological processes, biodiversity, and the overall health of the planet. It encourages the establishment of protected areas and the implementation of management plans to ensure the long-term conservation of wetland habitats.

2. International Cooperation: The Ramsar Convention facilitates international cooperation among member countries for the conservation and sustainable use of wetlands. It encourages the exchange of scientific knowledge, technical expertise, and information related to wetland conservation.

3. Identification and Designation of Wetlands of International Importance: The convention provides a framework for identifying and designating wetlands of international importance, also known as Ramsar sites. These sites are recognized for their significant ecological, botanical, zoological, limnological, or hydrological value. There are currently over 2,400 Ramsar sites around the world, covering a total area of over 250 million hectares.

4. Wise Use of Wetlands: The Ramsar Convention emphasizes the wise use of wetlands, taking into account the ecological, social, cultural, and economic aspects. It promotes sustainable development practices that maintain the ecological character of wetlands while providing benefits to local communities.

5. Public Awareness and Education: The convention encourages public awareness and education about the importance of wetlands and the need for their conservation. It promotes the involvement of local communities, indigenous peoples, and other stakeholders in wetland management and decision-making processes.

In conclusion, the Ramsar Convention is the international treaty that specifically protects wetlands on a global basis. It aims to conserve and sustainably manage wetlands, recognizing their ecological importance and the need for international cooperation in their conservation efforts.

Useful Microorganism: Rhizobium and Lactobacillus

Rhizobium:
- Rhizobium is a type of bacteria that forms a symbiotic relationship with legumes, such as peas, beans, and lentils.
- The bacteria infect the root nodules of these plants, forming a specialized structure called a bacteroid.
- Rhizobium helps in nitrogen fixation, which is the process of converting atmospheric nitrogen into a form that plants can use.
- This process is beneficial for both the bacteria and the host plant. The bacteria receive nutrients from the plant, while the plant gains a source of fixed nitrogen, which is essential for growth and development.
- The presence of Rhizobium bacteria in the soil can significantly improve the fertility of agricultural land by increasing nitrogen availability.

Lactobacillus:
- Lactobacillus is a genus of bacteria that is commonly found in the gut, as well as in fermented foods like yogurt and sauerkraut.
- These bacteria are considered beneficial because they help in maintaining a healthy balance of microorganisms in the gut, known as the gut microbiota.
- Lactobacillus produces lactic acid, which creates an acidic environment in the gut and inhibits the growth of harmful bacteria.
- They also help in the digestion and absorption of nutrients, produce vitamins, and support the immune system.
- Lactobacillus bacteria are often used as probiotics, which are live microorganisms that confer health benefits when consumed in adequate amounts.
- Probiotics containing Lactobacillus strains have been shown to have various positive effects on human health, including improving digestion, boosting the immune system, and reducing the risk of certain diseases.

Conclusion:
Both Rhizobium and Lactobacillus are useful microorganisms that play important roles in different ecosystems. Rhizobium helps in nitrogen fixation, enhancing soil fertility and promoting plant growth, while Lactobacillus contributes to gut health and overall well-being.

Explanation:

Source of Cod Liver Oil:
- Cod liver oil is obtained from fish, specifically from the liver of cod fish.

Vitamin D Content:
- Cod liver oil is known for its high vitamin D content, making it a popular supplement for individuals who may have vitamin D deficiency.

Benefits of Vitamin D:
- Vitamin D is essential for various bodily functions, including bone health, immune function, and mood regulation.

Other Nutrients:
- In addition to vitamin D, cod liver oil also contains omega-3 fatty acids, which are beneficial for heart health and reducing inflammation.

Usage of Cod Liver Oil:
- Cod liver oil can be consumed in liquid form or in capsule form as a dietary supplement.

Conclusion:
- Cod liver oil is a valuable source of vitamin D and other nutrients, making it a popular supplement for individuals looking to boost their intake of essential nutrients.

The sensation of a sound perceived in an ear is measured by another term called loudness which depends on intensity of sound and sensitiveness of the ear. Unit of loudness is bel. A practical unit of loudness is decibel (dB) which is 1/10th of bel. Another unit of loudness is phon.

Corneal blindness can be cured through corneal transplantation of donated eyes. Eye donors can belong to any age group or sex. People who use spectacles, or those operated for cataract, can still donate the eyes. People who are diabetic, have hypertension, asthma patients and those without communicable diseases can also donate eyes.

Tin utensils used to store food are made by electroplating a layer of tin over iron, because tin is less reactive than iron. Electroplating is the process of applying a layer of a metal over another by the means of electricity.

Plant Cell vs Animal Cell: Difference in Cell Walls

The correct answer to the given question is option 'A', which states that plant cells have cell walls while animal cells do not. Let us explore this difference in detail.

1. Plant Cell:
- Cell Wall: One of the key features of a plant cell is the presence of a rigid cell wall surrounding the cell membrane. The cell wall is made up of cellulose and provides structural support and protection to the cell.
- Cell Membrane: Plant cells also have a cell membrane, which is a selectively permeable barrier that controls the movement of substances in and out of the cell.
- Vacuole: Plant cells typically have a large central vacuole that helps maintain the cell's shape, stores water, nutrients, and waste products, and contributes to cell expansion and growth.
- Plastids: Plant cells contain various types of plastids, including chloroplasts (which carry out photosynthesis), chromoplasts (responsible for pigment synthesis), and leucoplasts (involved in storage of starch, oils, and proteins).

2. Animal Cell:
- Cell Membrane: Similar to plant cells, animal cells also have a cell membrane that regulates the movement of substances into and out of the cell.
- No Cell Wall: Unlike plant cells, animal cells lack a cell wall. Instead, they have a flexible and elastic cell membrane that allows them to change shape.
- No Central Vacuole: Animal cells may contain small vacuoles, but they are not as prominent or centrally located as in plant cells.
- Fewer Plastids: Animal cells generally have very few or no plastids. They do not possess chloroplasts and are unable to carry out photosynthesis.

Significance of Cell Walls in Plant Cells:
The presence of a cell wall in plant cells serves several important functions:
- It provides structural support and rigidity to the cell, allowing plants to maintain their shape even in the absence of external support.
- The cell wall acts as a barrier against mechanical stress and protects the cell from damage.
- It helps prevent excessive water uptake and maintains the osmotic balance of the cell.
- The cell wall contributes to the transport of water and nutrients through specialized structures called plasmodesmata.

In conclusion, the key difference between plant cells and animal cells lies in the presence of a cell wall, which is unique to plant cells. This cell wall provides structural support, protection, and several other functions that are essential for the survival and functioning of plants.

The correct answer is option 'D', neither 1 nor 2. Let's understand why this is the correct answer by analyzing each statement:

1. A female gamete is smaller than a male gamete and likely to be motile.
This statement is incorrect. In most organisms, including humans, the female gamete, which is the egg or ovum, is larger than the male gamete, which is the sperm. The egg is a non-motile gamete and does not have the ability to move on its own. It is usually stationary and waits to be fertilized by a sperm.

2. Male gametes are large and contain food-stores.
This statement is also incorrect. Male gametes, or sperm, are actually much smaller than female gametes. Sperm are highly specialized cells that are adapted for swimming to reach and fertilize the egg. They are streamlined and have a flagellum, or tail, which allows them to move. Sperm do not contain food-stores. Instead, they are equipped with mitochondria that provide energy for their movement.

Explanation:
It is important to understand the basic differences between male and female gametes. Gametes are reproductive cells that fuse during fertilization to form a new individual. In most organisms, including humans, the male gamete is called sperm and the female gamete is called the egg or ovum.

- Size and Motility:
- The female gamete, or egg, is much larger in size compared to the male gamete, sperm.
- The egg is non-motile and does not possess the ability to move on its own.
- On the other hand, sperm are much smaller in size and possess a flagellum that allows them to swim and reach the egg for fertilization.

- Nutrient Stores:
- The statement that male gametes contain food-stores is incorrect.
- Sperm do not contain food-stores but are equipped with mitochondria that provide energy for their movement.
- The female gamete, or egg, contains nutrient stores in the form of yolk, which provides nourishment for the developing embryo.

- Fertilization:
- During fertilization, a sperm penetrates the egg and fuses with it to form a zygote, which eventually develops into an embryo.
- The egg provides the necessary nutrients for the initial stages of development until the embryo can establish its own nutrient supply.

Conclusion:
In summary, the correct answer is option 'D', as both statements given in the question are incorrect. The female gamete is larger than the male gamete and is non-motile, while male gametes, or sperm, are smaller, motile, and do not contain food-stores.

The correct answer is option 'C' - Newton.

Newton is the SI unit of force. It is named after Sir Isaac Newton, a renowned physicist who made significant contributions to the field of mechanics. Newton's laws of motion form the foundation of classical physics, and the unit of force was named in his honor.

Here's a detailed explanation of why the SI unit of force is Newton:

1. Definition of Force:
- Force is defined as an external agent that can change the state of motion or shape of an object.
- It is a vector quantity, which means it has both magnitude and direction.

2. Newton's Second Law of Motion:
- Newton's second law of motion states that the force acting on an object is directly proportional to the rate of change of its momentum.
- Mathematically, F = ma, where F is the force, m is the mass of the object, and a is its acceleration.
- This equation shows that force is equal to the product of mass and acceleration.

3. SI Unit of Mass and Acceleration:
- The SI unit of mass is kilogram (kg). It is the base unit for mass in the International System of Units.
- The SI unit of acceleration is meter per second squared (m/s²). It is the rate of change of velocity per unit time.

4. SI Unit of Force:
- By substituting the SI units of mass (kg) and acceleration (m/s²) into Newton's second law of motion equation (F = ma), we get the SI unit of force as kg * m/s².
- This unit is known as Newton (N).

Therefore, the SI unit of force is Newton (N), which is equivalent to kg * m/s². It represents the amount of force required to accelerate a 1 kg mass by 1 meter per second squared.

In conclusion, the SI unit of force is Newton (N), and it is derived from Newton's second law of motion, which relates force, mass, and acceleration.

Respiration in Plants

Plants undergo respiration just like animals do. During respiration, plants take in air through small pores called stomata present on their leaves. The air contains oxygen and carbon dioxide. The process of respiration occurs in two stages:

1. Glycolysis - In this stage, glucose is broken down into pyruvate molecules. This process occurs in the cytoplasm of the plant cell and does not require oxygen.

2. Aerobic Respiration - In this stage, the pyruvate molecules produced in glycolysis are further broken down in the presence of oxygen. This process occurs in the mitochondria of the plant cell.

What Happens Next?

After taking in air during respiration, the plants utilize oxygen and give out carbon dioxide into the atmosphere. This is because during the second stage of respiration, the pyruvate molecules combine with oxygen to produce carbon dioxide, water, and energy.

The equation for respiration in plants is:

Glucose + Oxygen → Carbon Dioxide + Water + Energy

Therefore, the correct answer to the given question is option B, i.e., plants utilize oxygen and give out carbon dioxide during respiration.

The correct answer is option 'C' - 1, 3, and 5 only.

Explanation:
1. Arsenic: Arsenic contamination in drinking water is a major issue in many parts of India, particularly in the states of West Bengal, Bihar, Uttar Pradesh, and Assam. High levels of arsenic can cause various health issues, including skin problems, cancer, and organ damage.

2. Sorbitol: Sorbitol is a sugar alcohol commonly used as a sweetener in food and pharmaceutical products. It is not typically found as a pollutant in drinking water.

3. Fluoride: Fluoride contamination in drinking water is another significant problem in India, especially in states like Rajasthan, Gujarat, and Andhra Pradesh. High levels of fluoride can lead to dental and skeletal fluorosis, which cause severe damage to teeth and bones.

4. Formaldehyde: Formaldehyde is a colorless gas with a strong odor. It is not commonly found as a pollutant in drinking water in India.

5. Uranium: Uranium contamination in drinking water is a growing concern in several parts of India, including the states of Punjab, Rajasthan, and Jharkhand. High levels of uranium can have harmful effects on the kidneys and other organs.

Overall, the correct answer is option 'C' as both arsenic and fluoride are well-known pollutants in drinking water in some parts of India, while sorbitol, formaldehyde, and uranium are not commonly found contaminants.

According to Newton's second law, The rate of change of linear momentum of a body is directly proportional to the external force applied on the body , and takes place always in the direction of the force applied. So the rate of change of momentum is Force i.e. Newton's second law helps us to derive an equation for force.

Because the helium atoms are of lower mass than the average is molecules, the helium gas is less dense than air. The balloon thus weighs less than the air displaces by its volume.

Rabbi is a Hebrew term that means "my teacher" or "my master." It is a title given to Jewish religious leaders who have been ordained and have received extensive education in Jewish law, ethics, and traditions. Rabbis are responsible for interpreting religious texts, providing guidance to their communities, and leading religious services.

Alternative Name
The other name for rabbis is Hydrophobia. However, it is important to note that this answer is incorrect. The term "hydrophobia" does not have any connection to rabbis or their role in Judaism.

Explanation
The term "hydrophobia" is often used to refer to a symptom of rabies, a viral disease that affects the central nervous system of mammals. Rabies is typically transmitted through the bite or scratch of an infected animal. Symptoms of rabies include fever, headache, muscle aches, excessive salivation, and fear of water (hydrophobia). This fear of water is due to the difficulty in swallowing caused by the virus affecting the throat muscles.

Correct Answer
The correct answer to the question is not "hydrophobia." It is important to carefully read the options provided and select the correct answer, which is often based on knowledge and understanding of the topic being asked. In this case, the correct answer is not provided among the options given, as none of the options are alternative names for rabbis.

Heat flows from a body of higher temperature to a body of lower temperature. Here the temperature of both the objects is the same. So, heat will not flow from one object to another or there will not be any change in the temperature of both the two objects.

Adaptations of the Frog Differentiating it from the Fish

Introduction:
The frog belongs to the class Amphibia, while fish belong to the class Pisces. Although both frogs and fish are adapted to live in aquatic environments, there are certain adaptations that differentiate frogs from fish. One such adaptation is the ability of frogs to live in water as well as on land.

Ability to Live in Water and on Land:
Frogs possess the ability to live both in water and on land, whereas fish are exclusively aquatic organisms. This adaptation allows frogs to explore terrestrial habitats and exploit the resources available on land. Fish, on the other hand, lack limbs and other specialized structures required for movement on land.

Laying Eggs in Water:
Both frogs and fish lay eggs, but their modes of reproduction differ. Frogs lay their eggs in water, while fish lay their eggs in water as well. However, fish primarily reproduce through external fertilization, where the female releases eggs and the male simultaneously releases sperm over them. Frogs, on the other hand, undergo internal fertilization, where the male fertilizes the eggs inside the female's body before they are laid in water.

Streamlined Body:
Both frogs and fish possess streamlined bodies, but there are slight differences in their body shapes. Fish generally have a more streamlined body shape compared to frogs. This adaptation allows fish to move efficiently through water by reducing drag. Frogs, although not as streamlined as fish, have adapted to their semi-aquatic lifestyle by developing a body shape that enables them to move both in water and on land.

Presence of Mucous Glands in the Skin:
Frogs have mucous glands in their skin, while fish do not possess these specialized glands. These glands secrete a slimy substance called mucous, which helps frogs maintain their skin moist and protected. This adaptation is particularly important for frogs as they can easily dehydrate on land. Fish, on the other hand, have scales that provide protection against dehydration.

Conclusion:
In conclusion, the ability of frogs to live in both aquatic and terrestrial environments, along with their mode of reproduction, streamlined body shape, and presence of mucous glands in the skin, are adaptations that differentiate them from fish. These adaptations allow frogs to thrive in a variety of habitats and exploit resources both in water and on land.

Some of the most common properties of Aluminium are good thermal conductivity, malleability, light weight and high melting point which make it useful for making cooking utensils.

Tissues and Division of Labour in Multicellular Organisms

Tissues are groups of similar cells that work together to perform a specific function in the body. They are the building blocks of organs and are essential for the proper functioning of multicellular organisms. The presence of tissues in a multicellular organism ensures division of labour, which is the allocation of specific tasks to different groups of cells or tissues within the organism.

Division of Labour
- In a multicellular organism, different tissues are specialized to perform specific functions. This division of labour allows for more efficient functioning and higher overall productivity.
- Each tissue is specialized to carry out a particular function, such as protection, support, movement, or secretion.
- For example, muscle tissue is specialized for contraction and movement, while epithelial tissue is specialized for protection and secretion.
- This specialization allows the organism to perform complex tasks that would not be possible if all cells were identical and performed the same function.

Advantages of Division of Labour
- Increased Efficiency: Division of labour allows different tissues to focus on specific tasks, leading to increased efficiency in performing those tasks. Each tissue can develop specific adaptations and structures that enhance its function.
- Specialization: Different tissues can specialize in specific functions, which allows for the development of more complex and sophisticated organs and systems.
- Energy Conservation: Division of labour allows cells to specialize in certain functions, reducing the energy required for each cell to perform multiple tasks.
- Adaptability: The presence of specialized tissues allows multicellular organisms to adapt to different environments and perform a wide range of functions to ensure survival and reproduction.

Conclusion
The presence of tissues in a multicellular organism ensures division of labour, which is crucial for efficient functioning, specialization, energy conservation, and adaptability. By dividing tasks among different tissues, organisms can perform complex functions and enhance their overall fitness and survival.

Magnesium is a macronutrient of plants because it plays a crucial role in various physiological processes within the plant. Let us delve into the details of why magnesium is considered a macronutrient for plants.

1. Importance of Macronutrients:
Macronutrients are essential elements required in relatively large quantities by plants for their growth and development. These nutrients are vital for the plant's metabolism, as they are involved in various biochemical reactions.

2. Functions of Magnesium in Plants:
- Chlorophyll Production: Magnesium is a key component of chlorophyll, the pigment responsible for capturing sunlight during photosynthesis. It is an integral part of the chlorophyll molecule, assisting in the absorption of light energy necessary for the conversion of carbon dioxide and water into glucose and oxygen.
- Enzyme Activation: Magnesium is involved in activating numerous enzymes within the plant. Enzymes are proteins that facilitate biochemical reactions. Without sufficient magnesium, these enzymes may not function optimally, affecting the overall plant metabolism.
- Protein Synthesis: Magnesium is crucial for the synthesis of proteins in plants. It is required as a co-factor for many enzymes involved in protein production. Proteins are essential for various plant functions, including growth, development, and defense mechanisms.
- Nutrient Uptake and Transport: Magnesium plays a role in the uptake and transport of other nutrients within the plant. It helps in the absorption of phosphorus, nitrogen, and potassium, which are also macronutrients required by plants.
- Energy Transfer: Magnesium is involved in the transfer and storage of energy within the plant. It is a vital component of ATP (adenosine triphosphate), the molecule responsible for storing and transferring energy in cells.

3. Deficiency Symptoms:
A deficiency of magnesium in plants can lead to visible symptoms, such as yellowing of leaves (chlorosis) starting from the older leaves and progressing towards younger ones. This is because magnesium is mobile within the plant, and when it is limited, the plant redistributes it to the younger leaves, leaving the older leaves deficient. Additionally, reduced growth, poor fruit development, and impaired photosynthesis can also occur.

4. Sources of Magnesium:
Magnesium is naturally present in the soil and can be obtained by plants through their roots. Fertilizers containing magnesium, such as magnesium sulfate (Epsom salt), can also be applied to supplement magnesium levels in deficient soils.

In conclusion, magnesium is a macronutrient of plants because it plays a vital role in chlorophyll production, enzyme activation, protein synthesis, nutrient uptake, energy transfer, and overall plant metabolism. Its deficiency can lead to visible symptoms and impact plant growth and development.

First Oil Well in the World
The first oil well in the world was drilled in Pennsylvania.

Location
The well was drilled in Titusville, Pennsylvania, in 1859.

Importance
This drilling marked the beginning of the modern petroleum industry, as it was the first commercially successful oil well.

Driller
The well was drilled by Edwin Drake, a former railroad conductor who was hired by the Seneca Oil Company.

Method
Drake used a steam engine to drill the well, which reached a depth of 69 feet.

Production
The well produced around 25 barrels of oil per day, significantly boosting the industry in the region.

Impact
The success of this well led to a boom in oil exploration and drilling worldwide, transforming the energy industry.

Pair of Temperature Scales

Temperature is a measure of the degree of hotness or coldness of an object. There are several temperature scales that are used in different parts of the world. The most commonly used temperature scales are:

1. Fahrenheit scale (°F)
2. Celsius scale (°C)
3. Kelvin scale (K)

Equal Numerical Values

The question asks which of the following pairs may give equal numerical values of the temperature of a body. Let us look at each option one by one.

a) Fahrenheit and Kelvin

Fahrenheit and Kelvin are two different temperature scales. However, it is possible for a temperature in Fahrenheit to be equal to a temperature in Kelvin. This happens when the numerical value of the temperature in Fahrenheit is converted to Kelvin using a formula. The formula for converting Fahrenheit to Kelvin is:

T(K) = (T(°F) + 459.67) × 5/9

For example, a temperature of 212°F is equal to a temperature of 373.15 K. Therefore, option A is the correct answer.

b) Celsius and Kelvin

Celsius and Kelvin are also two different temperature scales. It is possible for a temperature in Celsius to be equal to a temperature in Kelvin, but this only happens when the temperature is equal to -273.15°C. This is known as absolute zero, which is the lowest possible temperature. Therefore, option B is not the correct answer.

c) Kelvin and Platinum

Kelvin is a temperature scale, but platinum is not. Therefore, option C is not the correct answer.

d) None of these

Option A is the correct answer, as explained above. Therefore, option D is not the correct answer.

Friction and Heat Generation

Rubbing of hands together in winters causes a sensation of warmth mainly because of the heat caused by the force of friction. When two surfaces are rubbed against each other, a force called friction is generated. Friction is the resistance to motion between two objects in contact with each other.

Friction and Heat Production

Friction converts mechanical energy into thermal energy, resulting in the generation of heat. This is known as the heat of friction. When we rub our hands together, the friction between the surfaces of our hands generates heat due to the resistance encountered during the rubbing motion.

Explanation of the Answer

The correct answer, option 'A', states that the sensation of warmth is caused by the heat generated by the force of friction. This answer is accurate because the rubbing motion between the hands creates friction, which in turn produces heat.

Friction and Molecular Activity

The heat generated by friction is a result of the increased molecular activity within the substances being rubbed. When two surfaces come into contact and rub against each other, the irregularities on the surfaces interlock and resist motion. This resistance causes the molecules in the surfaces to vibrate and collide, leading to an increase in kinetic energy and the generation of heat.

Thermal Energy Transfer

As the rubbing motion continues, the heat generated due to friction is transferred from the surface of one hand to the other. This transfer of thermal energy occurs through conduction, where heat flows from a region of higher temperature (the hand with more generated heat) to a region of lower temperature (the hand with less generated heat).

Sensation of Warmth

The sensation of warmth is felt as the heat from the friction is conducted to the skin. The increased temperature of the skin stimulates the nerve endings, which then send signals to the brain, resulting in the perception of warmth.

In conclusion, rubbing of hands together in winters causes a sensation of warmth mainly because of the heat generated by the force of friction. The rubbing motion generates friction, which converts mechanical energy into thermal energy, producing heat. This heat is then conducted to the skin, creating a feeling of warmth.

Epithelial Tissue: They are formed by cells which cover the external parts of the body organs and line the organ surfaces such as the surface of the skin, the reproductive tract, the airways, and the inner lining of the digestive tract. Functions of Epithelial Tissue

Kinetic Energy and Velocity

Kinetic energy is the energy possessed by an object due to its motion. It is directly proportional to the mass of the object and the square of its velocity. The formula for kinetic energy is given by:

K.E. = (1/2)mv^2

Where:
K.E. = Kinetic energy
m = Mass of the body
v = Velocity of the body

Effect of Doubling Velocity

When the velocity of a body is doubled, it means that the new velocity becomes twice the initial velocity. Let's assume the initial velocity of the body is 'u' and the new velocity is '2u'.

Comparing the Initial and Final Kinetic Energies
To understand the effect of doubling velocity on kinetic energy, let's compare the initial and final kinetic energies.

Initial Kinetic Energy:
K.E. = (1/2)mu^2

Final Kinetic Energy:
K.E. = (1/2)m(2u)^2
K.E. = (1/2)m(4u^2)
K.E. = 2mu^2

Comparing the initial and final kinetic energies, we observe that the final kinetic energy is four times the initial kinetic energy. Therefore, when the velocity of a body is doubled, its kinetic energy becomes four times larger.

Explanation:
The increase in kinetic energy is due to the fact that kinetic energy is directly proportional to the square of the velocity. When the velocity is doubled, the new velocity is squared, resulting in a four-fold increase in kinetic energy. This relationship can be understood by considering the formula for kinetic energy, where the velocity is squared.

Conclusion:
The kinetic energy of a body becomes four times larger when its velocity is doubled. This increase in kinetic energy is due to the direct relationship between kinetic energy and the square of velocity.