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.

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.

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

Option a

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.

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.

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.

Vaccination doesn't kill polio causing microbes.
Also it cannot prevent the entry of polio causing viruses.
It only creates immunity against the virus.

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.

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 Three Primary Nutrients for Plant Growth

The three primary nutrients needed for plant growth are nitrogen (N), phosphorus (P), and potassium (K). These nutrients are often referred to as macronutrients because plants require them in relatively large quantities compared to other essential elements.

Nitrogen (N)
- Nitrogen is essential for the growth and development of plants.
- It is a major component of amino acids, proteins, enzymes, and chlorophyll.
- Nitrogen is responsible for promoting leaf and stem growth.
- It helps in the production of healthy, lush foliage and enhances photosynthesis.
- Lack of nitrogen can result in stunted growth, yellowing of leaves (chlorosis), and poor overall plant health.

Phosphorus (P)
- Phosphorus plays a crucial role in energy transfer and storage within plants.
- It is necessary for the formation of ATP (adenosine triphosphate), which is the primary energy currency in cells.
- Phosphorus is involved in DNA and RNA synthesis, as well as the development of roots, flowers, and fruits.
- It aids in early root growth and establishment.
- Insufficient phosphorus can lead to poor root development, delayed flowering, and reduced fruit production.

Potassium (K)
- Potassium is vital for various physiological processes in plants.
- It helps in the activation of enzymes involved in photosynthesis and respiration.
- Potassium regulates water uptake and retention, enhancing the plant's ability to withstand drought and stress.
- It promotes strong stems and improves disease resistance.
- Lack of potassium can result in weakened plants, reduced fruit quality, and increased susceptibility to pests and diseases.

Conclusion
Nitrogen, phosphorus, and potassium are the three primary nutrients essential for plant growth. These macronutrients play crucial roles in various physiological processes and are necessary for the development of healthy and productive plants. By providing plants with adequate amounts of these nutrients, gardeners and farmers can ensure optimal growth, productivity, and overall plant health.

Explanation:

1. Chlorination for Drinking Water Purification:
- The statement that the chemical process of purifying drinking water is called chlorination is correct.
- Chlorination is a common method used to disinfect water by adding chlorine or chlorine compounds to the water.
- Chlorine kills bacteria and other microorganisms present in the water, making it safe for consumption.
- It is a crucial step in ensuring the safety of drinking water and preventing waterborne diseases.

2. Ganga Action Plan (GAP) for Ganges Pollution:
- The statement mentioning the Ganga Action Plan (GAP) being initiated in 1985 to protect the Ganges from pollution is also correct.
- The Ganga Action Plan was launched by the Government of India in 1985 with the aim of reducing pollution and improving the water quality of the Ganga River.
- The plan focused on the interception, diversion, and treatment of domestic sewage and industrial effluents flowing into the Ganges.
- It was one of the first major initiatives to clean up a polluted river in India and has since been followed by other similar projects for different rivers in the country.
Therefore, both statements are correct as chlorination is indeed used for water purification, and the Ganga Action Plan was indeed started in 1985 to address pollution in the Ganges.

Puberty usually occurs in girls between the ages of 10 and 14, while in boys it generally occurs later, between the ages of 12 and 16. In some African-American girls, puberty begins earlier, at about age 9, meaning that puberty occurs from ages 9 to 14.

Introduction:
The process of loosening and turning the soil is called ploughing. It is an important agricultural practice that helps prepare the soil for planting crops. Ploughing involves breaking up the soil, turning it over, and creating furrows for planting seeds.

Explanation:
Ploughing is an essential step in the cultivation of crops as it helps improve soil structure and fertility. It provides several benefits to the soil and the crops grown on it. Let's discuss these benefits in detail:

1. Loosening the soil:
Ploughing helps in loosening the compacted soil, which is necessary for the growth of plant roots. This process allows air, water, and nutrients to penetrate the soil more easily, promoting healthy root development.

2. Weed control:
Ploughing helps control weeds by uprooting and burying them deep into the soil. This prevents weed growth and competition with the cultivated crops. Turning the soil also exposes weed seeds to sunlight, which can inhibit their germination.

3. Enhancing soil aeration:
By breaking up the soil, ploughing improves soil aeration. This allows oxygen to reach the root zone, facilitating the respiration process of the plants. Adequate oxygen availability promotes healthy root growth and overall plant development.

4. Mixing organic matter:
During ploughing, organic matter such as crop residues or manure can be incorporated into the soil. This improves the soil's nutrient content, organic matter content, and overall fertility. Organic matter acts as a source of nutrients for the plants and also enhances the soil's water-holding capacity.

5. Pest and disease management:
Ploughing can help manage pests and diseases by burying crop residues and pathogens deep into the soil. This reduces the survival and spread of pests and diseases, minimizing their impact on subsequent crops.

Conclusion:
In conclusion, ploughing is the process of loosening and turning the soil, which is crucial for successful crop cultivation. It improves soil structure, enhances nutrient availability, controls weeds, and manages pests and diseases. Ploughing is an integral part of sustainable agricultural practices and plays a vital role in ensuring high crop yields.

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.

Introduction
Understanding sex hormones and their roles is essential in human biology. Let’s analyze the statements provided regarding sex hormones, particularly estrogen and testosterone.

Statement 1: Correct
- Estrogen and testosterone are indeed sex hormones.
- They play crucial roles in the development of secondary sexual characteristics:
- **Estrogen**: Promotes breast development, wider hips, and menstrual cycle regulation in females.
- **Testosterone**: Responsible for muscle mass, voice deepening, and facial hair growth in males.

Statement 2: Incorrect
- This statement incorrectly identifies the hormones:
- **Estrogen** is primarily a female hormone associated with female characteristics.
- **Testosterone** is primarily a male hormone associated with male characteristics.
- Therefore, the characterization in this statement is reversed.

Statement 3: Correct
- The secretion of estrogen and testosterone is regulated by hormones from the pituitary gland:
- **Follicle-stimulating hormone (FSH)** and **Luteinizing hormone (LH)** are secreted by the anterior pituitary.
- These hormones stimulate the gonads (ovaries in females and testes in males) to produce sex hormones.

Conclusion
- Based on the analysis:
- **Correct Statements**: 1 and 3
- **Incorrect Statement**: 2
- Hence, the correct answer is **option 'C': 1 and 3 only**.

Neem leaves are used to protect stored grains from insects and microorganisms. Neem, also known as Azadirachta indica, is a tree native to the Indian subcontinent. Its leaves have been traditionally used in various applications due to their medicinal and insecticidal properties.

The use of neem leaves for grain protection can be attributed to the following factors:

1. Insecticidal properties:
- Neem leaves contain various bioactive compounds such as azadirachtin, nimbin, and salannin, which exhibit strong insecticidal properties.
- These compounds disrupt the feeding, growth, and reproduction of insects, making them effective in controlling pest infestation in stored grains.
- Neem leaves act as a natural insecticide, preventing the growth and spread of insects that can damage stored grains.

2. Antimicrobial properties:
- Neem leaves possess antimicrobial properties that inhibit the growth of microorganisms such as bacteria and fungi.
- The bioactive compounds present in neem leaves, such as nimbin and gedunin, have been found to exhibit antimicrobial activity.
- By inhibiting the growth of microorganisms, neem leaves help in preventing the spoilage of stored grains and maintaining their quality.

3. Safe and eco-friendly:
- Neem leaves are a natural and safe option for grain protection as they do not pose any health hazards to humans or animals.
- Unlike synthetic chemical pesticides, neem leaves are biodegradable and do not contribute to environmental pollution.
- The use of neem leaves for grain protection aligns with sustainable and eco-friendly agricultural practices.

In conclusion, neem leaves are used to protect stored grains from insects and microorganisms due to their insecticidal and antimicrobial properties. The bioactive compounds present in neem leaves act as natural pesticides, effectively controlling pest infestation and preventing spoilage of stored grains. Additionally, the use of neem leaves is safe and environmentally friendly, making it a preferred choice for grain protection.

Understanding the Hydrogen Bomb
The hydrogen bomb, also known as a thermonuclear bomb, operates on the principle of thermonuclear fusion. This process involves the merging of light atomic nuclei to form heavier nuclei, releasing a tremendous amount of energy in the process.
Key Features of Thermonuclear Fusion
- Fusion Reaction: In a hydrogen bomb, isotopes of hydrogen, specifically deuterium and tritium, are fused together under extreme temperatures and pressures. This is similar to the processes that occur in the core of stars, including our Sun.
- Energy Release: The fusion of these hydrogen isotopes releases energy exponentially greater than that from traditional chemical explosives or fission reactions. This is due to the substantial binding energy that is released when nucleons combine into a more stable nucleus.
- Temperature and Pressure: The conditions necessary for fusion require temperatures in the order of millions of degrees Celsius, which is achieved through an initial fission explosion. This fission reaction acts as a trigger for the subsequent fusion process.
Why Not Controlled Fusion or Fission?
- Controlled Fusion Reaction: While research into controlled fusion (like that in fusion reactors) aims to harness energy from fusion safely, hydrogen bombs do not employ this method, as they are designed for explosive power rather than energy generation.
- Fission: Controlled fission reactions, as found in nuclear reactors, involve splitting heavy nuclei (like uranium or plutonium) and do not produce the same energy levels or mechanisms involved in the hydrogen bomb's operation.
In conclusion, the hydrogen bomb is fundamentally based on thermonuclear fusion reactions, making option 'B' the correct choice.

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.

Meristematic Tissue: They are the group of young cells, which consists of actively dividing cells and leads to increase in length and thickness of the plant. There are different types of meristematic tissues, which are classified on the basis of positions, functions, plane of divisions, origin and development. The three main types of meristematic tissues depending on the occurrence of the meristematic tissue on the plant body are

Characteristics of Spirogyra:

Spirogyra is a type of filamentous green algae with unique characteristics that set it apart from other organisms. Here are some key features that describe Spirogyra:

- Filamentous Structure: Spirogyra has a filamentous body structure, consisting of long, unbranched chains of cells.

- Presence of Cytoplasmic Strands: The cells of Spirogyra contain spiral-shaped chloroplasts, which are interconnected by cytoplasmic strands.

- Presence of Pyrenoids: Spirogyra cells also contain pyrenoids, which are specialized structures involved in the storage of starch.

These characteristics make Spirogyra a distinctive organism within the plant kingdom, and contribute to its ability to carry out photosynthesis and thrive in aquatic environments.

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

Explanation:

Newton’s first law of motion states that an object at rest will remain at rest and an object in motion will remain in motion with a constant velocity unless acted upon by a net external force. This is also known as the law of inertia.

When a car is in motion, the passengers inside the car are also in motion. When the car stops suddenly due to an emergency braking, the passengers inside the car tend to continue their motion in the same direction due to the law of inertia. This means that the passengers tend to move forward in the direction of the car’s motion before it stopped suddenly. This is the reason why a person falls forward on sudden stopping of the car.

The seat belts are designed to prevent this forward motion of the passengers. When a car stops suddenly, the seat belt applies a force on the passenger in the opposite direction to their motion, which helps to slow down their forward motion and bring them to a stop. This prevents the passengers from getting injured due to the sudden stop.

Conclusion:

Therefore, it can be concluded that a person falls in forward direction on the sudden stopping of the car due to Newton’s first law of motion, which is the law of inertia. The seat belts in the cars are designed to prevent this forward motion of the passengers and protect them from getting injured.

Explanation:

The correct answer is option B: It will spread the force of the bag over the large area of the shoulder of the child producing less pressure.

Reasoning:

When designing school bags, it is important to consider the well-being and comfort of the students who will be carrying them. Broad strips on school bags serve a specific purpose, which is to distribute the force exerted by the bag over a larger surface area of the shoulder. This helps in reducing the pressure exerted on the shoulder and provides a more comfortable carrying experience for the child.

Advantages of Broad Strips:

1. Force Distribution: Broad strips on school bags help in spreading the force exerted by the bag over a larger area of the shoulder. This means that the weight of the bag is distributed more evenly, reducing the pressure on a specific point on the shoulder. This is especially important when students have to carry heavy books and other items in their bags.

2. Less Pressure: By distributing the force over a larger area, the pressure exerted on the shoulder is reduced. This can help prevent shoulder pain, discomfort, and even potential injuries that may arise from carrying heavy bags with narrow straps.

3. Improved Comfort: The use of broad straps on school bags enhances the overall comfort of carrying the bag. The broader straps provide better support and stability to the bag, allowing the child to carry it with ease for extended periods of time.

4. Prevention of Shoulder Strain: Carrying heavy bags with narrow straps can lead to strain on the shoulders, neck, and back. Broad straps help in minimizing this strain by evenly distributing the weight, reducing the risk of musculoskeletal issues.

5. Longevity of the Bag: By spreading the force over a larger area, the pressure on the straps themselves is reduced. This helps in preventing wear and tear on the straps, increasing the overall durability and longevity of the bag.

In conclusion, the provision of broad strips on school bags is beneficial as it spreads the force of the bag over a larger area of the shoulder, resulting in less pressure and improved comfort for the child.

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.

The current flowing through a conductor is directly proportional to magnetic field. As the electric current through the wire increases, the magnitude of the magnetic field produced at a given point increases.

Explanation:

Regions close to the equator get maximum heat from the Sun:
- This assertion is correct as the regions near the equator receive direct sunlight throughout the year, leading to higher temperatures compared to regions further away from the equator.

Warm air rises, and cooler air from the 0-30 degrees latitude belt moves towards the equator:
- This assertion is also correct as warm air near the equator rises, creating a low-pressure area. Cooler air from the regions around 0-30 degrees latitude moves in to replace the rising warm air, creating a wind pattern known as the Hadley Cell.

Wind flows from 60° latitude to 30° latitude due to uneven heating:
- This assertion is incorrect. The wind actually flows from 30° latitude to 60° latitude due to the temperature difference between these regions. The warm air near the equator rises, moves towards the poles, cools down, sinks at around 30° latitude, and then flows back towards the equator at the surface level.
Therefore, the correct assertions are 1 and 2 only.