Biology Quiz - 1, General Knowledge - Railways MCQ

What is baking soda?
Baking soda, also known as sodium bicarbonate, is a chemical compound that is commonly used in cooking and baking. It is a white crystalline powder with a slightly alkaline taste.
Explanation:
Sodium bicarbonate:
- Baking soda is chemically known as sodium bicarbonate (NaHCO3).
- It is a compound made up of sodium (Na), hydrogen (H), carbon (C), and oxygen (O) atoms.
- Sodium bicarbonate is a weak base and can react with acids to produce carbon dioxide gas, which helps baked goods rise.
Key Points:
- Baking soda is sodium bicarbonate.
- It is commonly used in cooking and baking.
- It is a white crystalline powder with a slightly alkaline taste.
- Sodium bicarbonate is a weak base and reacts with acids to produce carbon dioxide gas.

Ozone Hole
The ozone hole refers to the depletion or thinning of the ozone layer in the stratosphere. This phenomenon is most prominent over Antarctica but can also occur in other regions of the Earth's atmosphere. Here is a detailed explanation of the ozone hole:
1. What is the ozone layer?
- The ozone layer is a region in the Earth's stratosphere that contains a high concentration of ozone molecules (O3).
- It plays a crucial role in protecting life on Earth by absorbing most of the sun's harmful ultraviolet (UV) radiation.
2. Causes of the ozone hole:
- The primary cause of the ozone hole is the release of certain human-made chemicals called ozone-depleting substances (ODS), including chlorofluorocarbons (CFCs), halons, and carbon tetrachloride.
- These chemicals contain chlorine and bromine atoms, which can destroy ozone molecules when they reach the stratosphere.
3. Effects of ozone depletion:
- Ozone depletion leads to an increase in harmful UV radiation reaching the Earth's surface.
- High levels of UV radiation can have detrimental effects on human health, such as skin cancer, cataracts, and weakened immune systems.
- It can also harm marine ecosystems, agriculture, and the overall balance of the Earth's atmosphere.
4. Ozone hole formation:
- The ozone hole is primarily observed over Antarctica during the Southern Hemisphere's spring (September to November).
- During this time, polar stratospheric clouds form, providing a surface for chemical reactions involving ODS.
- These reactions release chlorine and bromine atoms, which then catalytically destroy ozone molecules.
5. Ozone hole recovery:
- The Montreal Protocol, an international environmental agreement, was established in 1987 to reduce and eliminate the production and consumption of ODS.
- As a result of the protocol, the production of most ODS has been phased out, leading to a gradual recovery of the ozone layer.
- However, complete recovery is expected to take several decades.
In conclusion, the ozone hole refers to the depletion and thinning of the ozone layer in the stratosphere, primarily caused by human-made chemicals. It has significant implications for human health and the environment.

Timber-yielding Plants
- Pine, fir, spruce, cedar, larch, and cypress are popular timber-yielding plants.
- These plants are found in hilly regions of India.
Classification
These timber-yielding plants belong to the category of gymnosperms.
Gymnosperms
- Gymnosperms are a group of plants that produce naked seeds, meaning the seeds are not enclosed in a fruit.
- They are known for their woody cones that contain the seeds.
- Gymnosperms include conifers like pine, fir, spruce, cedar, larch, and cypress.
Difference from Angiosperms
- Angiosperms are another major group of plants that produce seeds enclosed within a fruit.
- Unlike gymnosperms, angiosperms have flowers and fruits.
- Examples of angiosperms include apple trees, rose bushes, and wheat plants.
Importance of Gymnosperms
- Gymnosperms are important for their timber production.
- The wood obtained from these plants is commonly used in construction, furniture making, and many other applications.
- They also contribute to the ecological balance by providing habitat and food for various organisms.
Conclusion
Pine, fir, spruce, cedar, larch, and cypress, which are famous timber-yielding plants found in the hilly regions of India, belong to the group of gymnosperms. Gymnosperms are characterized by the production of naked seeds and the absence of flowers and fruits.

Pollination: Transfer of pollen from anther to stigma
Pollination is a crucial step in the reproductive process of flowering plants. It involves the transfer of pollen grains from the male reproductive organ, the anther, to the female reproductive organ, the stigma. This process is essential for successful fertilization and the production of seeds.
Here is a detailed explanation of why option A, "transfer of pollen from anther to stigma," is the correct definition of pollination:
1. Pollen transfer: Pollination involves the transfer of pollen grains, which contain the male gametes, from the anther to the stigma of a flower. This transfer can occur through various mechanisms such as wind, water, animals, or self-pollination.
2. Anther and stigma: The anther is the male reproductive part of a flower, where pollen grains are produced. The stigma, on the other hand, is the female reproductive part that receives pollen grains for fertilization.
3. Purpose of pollination: Pollination is necessary for the fertilization of the ovules present in the ovary of a flower. When pollen grains land on the stigma, they germinate and produce a pollen tube that grows down into the ovary. This tube delivers the male gametes to the ovules, resulting in fertilization.
4. Different pollinators: Pollination can be carried out by various agents, including insects, birds, bats, wind, and water. Insect pollination is the most common and efficient method, with bees being the most important pollinators.
5. Importance of pollination: Pollination is vital for the reproduction and survival of flowering plants. It ensures genetic diversity by facilitating cross-pollination between different plants, leading to the production of seeds and fruits.
In conclusion, option A is the best definition of pollination as it accurately describes the transfer of pollen from the anther to the stigma, which is essential for fertilization and the production of seeds in flowering plants.

Plants receive their nutrients mainly from the soil.
There are several essential nutrients that plants need in order to grow and thrive. These nutrients are mainly obtained from the soil through the plant's root system. Here's a detailed explanation of how plants receive their nutrients from the soil:
1. Root Structure:
- Plants have a complex root system that consists of the main root, called the taproot, and smaller, branching roots known as lateral roots.
- These roots are responsible for absorbing water and nutrients from the soil.
2. Nutrient Absorption:
- The root hairs, which are tiny extensions of the root, increase the surface area of the root and facilitate nutrient absorption.
- Nutrients are absorbed by the roots through a process called active transport, where the plant actively takes in specific ions from the soil.
3. Soil Composition:
- The soil contains a variety of essential nutrients that plants need, including macronutrients like nitrogen (N), phosphorus (P), and potassium (K), as well as micronutrients like iron (Fe), manganese (Mn), and zinc (Zn).
- These nutrients are present in the soil in different forms, and plants have specific mechanisms to uptake and utilize them.
4. Root Interactions:
- Plants also interact with beneficial microbes in the soil, such as mycorrhizal fungi, which form symbiotic relationships with the plant roots.
- These microbes help in nutrient uptake by increasing the surface area of the roots and enhancing nutrient availability.
5. Nutrient Transport:
- Once the nutrients are absorbed by the roots, they are transported through the plant's vascular system, primarily through the xylem, to different parts of the plant.
- This allows the nutrients to be distributed to areas where they are needed for growth, such as the leaves, stems, and reproductive organs.
In conclusion, while plants obtain energy from sunlight through the process of photosynthesis, they mainly receive their nutrients from the soil through their root system. The roots absorb essential nutrients from the soil, and these nutrients are then transported throughout the plant to support growth and development.

Active transport, this is the only transport method that can move species against their concentration gradient (from low to high concentration). Facilitated diffusion only moves species down their concentration gradient from high to low concentration.

Photosynthesis generally takes place in which parts of the plant?
Photosynthesis generally takes place in the following parts of the plant:
1. Leaf:
- The primary site of photosynthesis in most plants.
- Contains specialized structures called chloroplasts that contain the pigment chlorophyll, which is responsible for capturing sunlight.
2. Other chloroplast-bearing parts:
- In addition to leaves, certain plant parts like stems and fruits may also contain chloroplasts.
- These chloroplasts enable photosynthesis to occur in these parts as well.
3. Stem:
- While not as common as in leaves, some plants have specialized stem tissues called green stems that contain chloroplasts and can carry out photosynthesis.
4. Fruit:
- In some fruits, especially those that turn green when they ripen, photosynthesis can occur in the chloroplasts present in the fruit's skin or pulp.
Therefore, the correct answer is A: Leaf and other chloroplast-bearing parts. These are the primary locations where photosynthesis takes place in plants.

option ( a) is correct answer. 

Explanation ;-

Many species of Bony fish have an organ called swim bladder a long chamber of soft flexible walls glasses from inside the fish body can diffuse into this chamber does increasing  the volume this helps in the rising of the fish to  the surface of the water when gas is contained in the chamber are released the walls of  the chamber collapse there by decreasing the volume and hence a decrease in upthrust the fish go deep into the water hence digesting the value of sin letter to the required extend the fish can stay at any level in the water.

Plants synthesize protein from amino acids

Explanation:

Plants go through the process of protein synthesis to produce the proteins they need for various functions in their cells. This process involves the conversion of amino acids into proteins.

Here is a detailed explanation of how plants synthesize protein from amino acids:
1. Plant nutrition: Plants obtain nutrients from the soil, including minerals and water. They also produce their own food through the process of photosynthesis.
2. Protein formation: Proteins are essential for the structure and function of plant cells. They are involved in various processes, such as enzyme activity, cell signaling, and transportation of molecules.
3. Amino acid uptake: Plants absorb amino acids from the soil through their root systems. Amino acids are the building blocks of proteins.
4. Transportation: Once absorbed, the amino acids are transported to different parts of the plant through the vascular system, including the xylem and phloem.
5. Protein synthesis: Inside the plant cells, the process of protein synthesis takes place. It involves the assembly of amino acids into polypeptide chains, which then fold into functional proteins.
6. Ribosomes: Ribosomes, which are located in the cytoplasm of plant cells, are responsible for protein synthesis. They read the genetic information stored in the plant's DNA and use it to assemble the correct sequence of amino acids.
7. Transcription and translation: The process of protein synthesis involves two main steps: transcription and translation. During transcription, the DNA sequence is copied into a molecule called messenger RNA (mRNA). This mRNA then travels to the ribosomes, where translation occurs. During translation, the ribosomes read the mRNA sequence and assemble the corresponding amino acids into a protein chain.
8. Post-translational modifications: After protein synthesis, the newly formed proteins may undergo post-translational modifications, such as folding, chemical modifications, and targeting to specific cellular compartments.
9. Protein function: Once synthesized and modified, the proteins perform their specific functions within the plant cells. This can include enzyme activity, structural support, defense against pathogens, and many other vital processes.
In conclusion, plants synthesize protein from amino acids, which they obtain from the soil and transport to various parts of the plant. The process of protein synthesis involves the assembly of amino acids into polypeptide chains, which then fold into functional proteins. These proteins play essential roles in plant growth, development, and overall functioning.

Plants absorb dissolved nitrates from soil and convert them into free nitrogen. Plants also take nitrogen from the soil in the form of ammonium ions. Nitrate exists in the inorganic form in the environment. Plant absorbs nitrates from soil for the formation of protein. The process of Conversion of nitrates into nitrogen by anaerobic bacteria is called denitrification.

Explanation:
The question states that out of 900 reported species of gymnosperms, conifers make up about 500 species. It also mentions that there are approximately 250,000 species of angiosperms (flowering plants) in the world. The question asks which type of plants dominate the woodlands in Europe, Asia, North America, and mountains like the Himalayas.
To answer this question, we need to understand the characteristics and distribution of gymnosperms and angiosperms:
1. Gymnosperms:
- Gymnosperms are a group of plants that produce seeds but do not have flowers or fruits.
- Conifers are a type of gymnosperm that includes trees like pines, spruces, firs, and cedars.
- They are typically found in colder regions, such as boreal forests, and are well-adapted to survive in harsh conditions.
2. Angiosperms:
- Angiosperms are flowering plants that produce seeds enclosed within a fruit.
- They are the most diverse and widespread group of plants, found in nearly all habitats worldwide.
- Angiosperms include trees, shrubs, herbs, and grasses.
Based on this information, we can conclude that the dominant woodlands in Europe, Asia, North America, and mountains like the Himalayas are mainly populated by conifers, which are a type of gymnosperm. Therefore, the correct answer is option C: only conifers.

Explanation:
The correct answer is C: Secretion of hormones for calcium regulation in blood and bones. Here is a detailed explanation of why this is not a function of bones:
Functions of Bones:
A: Place for muscle attachment:
- Bones provide a structure for muscles to attach to, allowing them to move and perform their functions.
- Muscles exert force on bones, causing them to move and carry out various bodily movements.
B: Protection of vital organs:
- Bones act as a protective shield for vital organs in the body.
- For example, the skull protects the brain, the ribcage protects the heart and lungs, and the spinal column protects the spinal cord.
D: Production of blood corpuscles:
- Certain bones in the body, such as the bone marrow, are responsible for the production of blood cells.
- Red blood cells, white blood cells, and platelets are produced in the bone marrow, which is located inside certain bones.
C: Secretion of hormones for calcium regulation in blood and bones:
- This statement is incorrect as bones do not secrete hormones for calcium regulation.
- Hormones like parathyroid hormone (PTH) and calcitonin are responsible for regulating calcium levels in the blood and bones, but they are not secreted by the bones themselves.
In summary, bones have several important functions, including providing a place for muscle attachment, protecting vital organs, and producing blood cells. However, bones do not secrete hormones for calcium regulation in the blood and bones.

Plants absorb most part of water needed by them through their root hairs.
Explanation:
- Root hairs are tiny, finger-like projections that extend from the surface of the root cells.
- They are located in the zone of maturation, which is the area of the root where cells differentiate into specific tissues.
- The root hairs greatly increase the surface area of the root, allowing for more efficient absorption of water and nutrients.
- The process of water absorption in plants is called osmosis.
- Osmosis is the movement of water molecules from an area of lower solute concentration to an area of higher solute concentration through a semi-permeable membrane.
- The root hairs have a higher concentration of solutes than the surrounding soil, creating a concentration gradient that drives the movement of water into the plant.
- Water enters the root hairs through osmosis and then moves through the root tissues to other parts of the plant.
- Root hairs also play a role in absorbing dissolved nutrients from the soil, which are essential for plant growth and development.
- The absorbed water and nutrients are transported upward through the xylem vessels to the rest of the plant.
- While other parts of the root, such as the embryonic zone, growing point, and zone of elongation, also contribute to water absorption, root hairs are the primary site of water uptake in plants.
Therefore, the correct answer is C: root hairs.

Introduction:
Photo-oxidation refers to the process of light and oxygen-induced breakdown. It involves the degradation of organic compounds due to the exposure to light and the presence of oxygen. There are several mechanisms by which photo-oxidation can occur, including photorespiration and photolysis.
Explanation:
Here is a detailed explanation of each option and why the correct answer is "D: All of the above":
A: Photorespiration:
- Photorespiration is a metabolic pathway that occurs in plants during photosynthesis.
- It involves the oxidation of organic compounds, such as sugars, in the presence of light and oxygen.
- Photorespiration can lead to the breakdown of organic molecules and the release of carbon dioxide.
- While photorespiration is a specific form of photo-oxidation, it does not encompass all types of light and oxygen-induced breakdown.
B: Photolysis:
- Photolysis refers to the process of chemical decomposition or breakdown due to the absorption of light.
- It involves the breaking of chemical bonds in a molecule, resulting in the formation of new compounds.
- Photolysis can occur in the presence of oxygen, leading to the oxidation of organic compounds.
- Like photorespiration, photolysis is a specific type of photo-oxidation but does not encompass all forms of light and oxygen-induced breakdown.
C: Light and oxygen-induced breakdown:
- This option refers to the general process of organic compound degradation due to the combined effects of light and oxygen.
- When organic compounds are exposed to light and oxygen, various chemical reactions can occur, leading to their breakdown.
- These reactions may involve oxidation, photolysis, or other processes.
- Light and oxygen-induced breakdown is a broader term that encompasses both photorespiration and photolysis.
D: All of the above:
- The correct answer is "D: All of the above" because all of the options mentioned (photorespiration, photolysis, and light and oxygen-induced breakdown) are forms of photo-oxidation.
- Photo-oxidation refers to the overall process of organic compound degradation due to the combined effects of light and oxygen.
- While photorespiration and photolysis are specific forms of photo-oxidation, light and oxygen-induced breakdown is a more general term that encompasses all types of light and oxygen-induced degradation.
Conclusion:
In summary, photo-oxidation is the process of light and oxygen-induced breakdown of organic compounds. It includes specific mechanisms such as photorespiration and photolysis, as well as other types of degradation. Therefore, the correct answer is "D: All of the above."

The Process of Cell Division
Cell division is a vital process in living organisms for growth, development, and reproduction. It involves the division of a single cell into two daughter cells, each containing a complete set of genetic material. There are several methods of cell division, but one of the most common and well-known processes is mitosis.
Mitosis
Mitosis is a type of cell division that occurs in eukaryotic cells. It involves the replication and distribution of genetic material to ensure that each daughter cell receives a complete set of chromosomes. The process of mitosis can be divided into several stages:
1. Interphase: This is the phase before mitosis where the cell prepares for division by growing, replicating its DNA, and producing additional organelles.
2. Prophase: During prophase, the chromatin condenses into visible chromosomes, and the nuclear envelope starts to break down. The centrioles also move to opposite poles of the cell, forming the spindle fibers.
3. Metaphase: In metaphase, the chromosomes align at the equatorial plane of the cell. The spindle fibers attach to the centromeres of the chromosomes.
4. Anaphase: During anaphase, the sister chromatids separate and move towards opposite poles of the cell. The spindle fibers shorten, pulling the chromosomes apart.
5. Telophase: In telophase, the chromosomes reach the poles of the cell, and the nuclear envelope reforms around each set of chromosomes. The chromosomes begin to decondense.
6. Cytokinesis: Cytokinesis is the final stage of cell division, where the cytoplasm divides, and two daughter cells are formed. In animal cells, a cleavage furrow forms, pinching the cell in two, while in plant cells, a cell plate forms to separate the daughter cells.
Other Methods of Cell Division
While mitosis is the most common process of cell division, there are other methods that can take place depending on the organism and specific purposes:
1. Meiosis: Meiosis is a specialized form of cell division that occurs in sexually reproducing organisms. It involves two rounds of division, resulting in the formation of four daughter cells with half the number of chromosomes as the parent cell. Meiosis is essential for the production of gametes (sperm and eggs) and genetic diversity.
2. Binary fission: Binary fission is a form of cell division that occurs in prokaryotes, such as bacteria. It involves the replication of the bacterial DNA and the division of the cell into two daughter cells.
3. Budding: Budding is a type of cell division that occurs in some organisms, such as yeast and hydra. It involves the outgrowth of a new cell from the parent cell, which eventually detaches to become an independent organism.
4. Fragmentation: Fragmentation is a form of cell division that occurs in some organisms, such as flatworms and plants. It involves the breaking of the parent organism into fragments, with each fragment capable of regenerating into a new individual.
Conclusion
Cell division is a complex process that plays a crucial role in the growth, development, and reproduction of organisms. Mitosis is the most common method of cell division in eukaryotes, ensuring the accurate distribution of genetic material to daughter cells. However, other methods, such as meiosis, binary f

Most highly intelligent mammals are:
- Whales
- Dolphins
- Elephants
- Kangaroos
Explanation:
Intelligence in mammals can be measured in various ways, such as problem-solving ability, social behavior, communication skills, and memory. Based on these criteria, the following mammals are considered highly intelligent:
1. Whales: Whales, particularly the species like the orca or killer whale, are known for their intelligence. They exhibit complex social structures, communicate through a variety of vocalizations, and display problem-solving abilities. Their large brains and intricate behaviors indicate high intelligence.
2. Dolphins: Dolphins are renowned for their intelligence. They have excellent problem-solving skills, display self-awareness, and exhibit complex communication through a combination of vocalizations and body language. Their ability to learn and use tools further highlights their intelligence.
3. Elephants: Elephants possess remarkable cognitive abilities. They have excellent memory, show empathy and compassion towards their herd members, and demonstrate problem-solving skills. Their ability to use tools and their complex social structures contribute to their high intelligence.
4. Kangaroos: While kangaroos may not be as commonly associated with high intelligence as whales, dolphins, or elephants, they still display remarkable cognitive abilities. They exhibit social learning, problem-solving skills, and possess excellent memory. Kangaroos have been observed using their forelimbs to manipulate objects, which suggests a certain level of intelligence.
Overall, while there may be other highly intelligent mammals, whales, dolphins, elephants, and kangaroos are among the most notable examples. Their cognitive abilities, social behaviors, and problem-solving skills contribute to their classification as highly intelligent mammals.

Plant development is influenced by:
Quality of light:
- Different wavelengths of light have different effects on plant growth and development.
- Plants use specific wavelengths of light, such as red and blue light, for photosynthesis.
- Quality of light also affects the timing of flowering and fruiting in plants.
Quantity of light:
- The intensity or brightness of light affects the rate of photosynthesis in plants.
- Plants require a certain amount of light to produce enough energy for growth and development.
- Insufficient light can lead to weak and spindly growth, while excessive light can cause damage to plant tissues.
Duration of light:
- The length of time that plants are exposed to light, also known as photoperiod, influences various developmental processes.
- For example, some plants require specific day lengths to initiate flowering.
- The duration of light also affects the production of certain hormones that regulate plant growth.
Overall:
- Plant development is influenced by the quality, quantity, and duration of light.
- The specific combination of these factors determines how plants grow, flower, and produce fruits.
- Understanding and manipulating these factors can be used in horticulture and agriculture to optimize plant growth and productivity.

Prokaryotic cells lack:
- Nucleolus: Prokaryotic cells do not have a distinct nucleolus, which is a substructure found within the nucleus of eukaryotic cells. The nucleolus is responsible for the production and assembly of ribosomes.
- Nuclear membrane: Prokaryotic cells lack a true nuclear membrane or nuclear envelope. Instead, their genetic material is found in a region called the nucleoid, which is not enclosed by a membrane. This means that the genetic material is not separated from the cytoplasm.
- Membrane-bound organelles: Prokaryotic cells do not possess any membrane-bound organelles, such as mitochondria, chloroplasts, or endoplasmic reticulum. These organelles are characteristic of eukaryotic cells and are responsible for various cellular functions.
- All of these: Therefore, the correct answer is option D, which states that prokaryotic cells lack all of the mentioned features.
In summary, prokaryotic cells lack a nucleolus, nuclear membrane, and membrane-bound organelles. These features are unique to eukaryotic cells and contribute to their complex structure and function. Prokaryotic cells, on the other hand, are simpler in structure and lack these specific characteristics.

In red light the rate of synthesis is better because chlorophylls can easily and effectively absorb specifically red light from the white light. ie, Plants, just like us can only tolerate certain wavelengths of light, especially for the chemical reactions of photosynthesis. So we can say chlorophyll pigment absorbs red light the best .Since white light is a mixture of several wavelengths of color and the chlorophyll in green leaves absorbs energies from all visible light except green .Then exposing white light to a plant will result in the fastest rate of photosynthesis followed by red . Green or yellow light will have the slowest rates of phtosynthesis because they are reflected by the pigments of plants.So the answer will be white light.

Now I will explain the reason.

In Photosynthesis, there is a reaction center as you can see the dark colored sphere in the middle and the light green spheres are the antenna molecules.

The antenna molecules do the work of supplying the energy to the reaction center and the reaction center itself also captures photon’s energy to excite the electrons.

The reaction center’s favorite light is red but the antenna molecules also absorb other wavelengths. That is the reason white light leads to faster or higher photosynthesis as compared to red or other light alon

Discovery of the Nucleus

• Robert Brown: Robert Brown was the scientist who first discovered the presence of the nucleus in cells.


• Year of Discovery: The discovery of the nucleus took place in 1831.


• Role of the Nucleus: The nucleus is a rounded body within each cell that contains genetic material.


• Importance of the Discovery: The discovery of the nucleus was a significant milestone in the field of biology, as it led to a better understanding of cellular structure and function.

Other Options:

• Robert Hooke: Although Robert Hooke made important contributions to the field of microscopy, he did not discover the nucleus.


• Rudolf Virchow: Rudolf Virchow was a German physician and pathologist who made significant contributions to the development of cell theory, but he did not discover the nucleus.


• Theodore Schwann: Theodore Schwann was a German physiologist who formulated the cell theory along with Matthias Schleiden, but he did not discover the nucleus.

Therefore, the correct answer is Robert Brown (B) as he was the scientist who first discovered the presence of the nucleus in cells in 1831.

Primary phloem develops from provascular tissue.
The development of primary phloem occurs through several stages, starting from the provascular tissue. Here is a detailed explanation:
Provascular tissue formation:
- The provascular tissue is formed during embryogenesis in the apical meristem of the growing plant.
- The provascular tissue gives rise to the primary vascular system, including both xylem and phloem.
Formation of procambium:
- Within the provascular tissue, certain cells differentiate into a meristematic tissue called procambium.
- Procambium is responsible for the formation of primary vascular tissues, including primary phloem.
Differentiation of primary phloem:
- As the procambium cells divide and elongate, they differentiate into primary phloem cells.
- These cells undergo structural and functional modifications to become specialized for the transport of sugars, nutrients, and signaling molecules.
Maturation of primary phloem:
- The primary phloem cells undergo further maturation, including the formation of sieve elements and companion cells.
- Sieve elements are responsible for the long-distance transport of nutrients, while companion cells support the metabolic needs of sieve elements.
Transport function:
- Once fully developed, the primary phloem serves as the main conduit for the transport of organic materials, such as sugars, throughout the plant.
- It plays a crucial role in the distribution of nutrients and energy to various parts of the plant.
In summary, primary phloem develops from provascular tissue, specifically from the procambium cells. These cells undergo differentiation and maturation to form the functional primary phloem, which is essential for nutrient transport in plants.

Anopheles mosquitoes as vectors:

Anopheles mosquitoes are known for transmitting malaria, but they can also act as vectors for other diseases. One of these diseases is filariasis, caused by parasitic worms. Below are the details of the diseases transmitted by anopheles mosquitoes:

• Dengue Fever (A): Anopheles mosquitoes are not vectors for dengue fever. Dengue is mainly transmitted by Aedes mosquitoes.


• Filariasis (B): Anopheles mosquitoes can transmit filariasis, a disease caused by parasitic worms that affect the lymphatic system.


• Encephalitis (C): Anopheles mosquitoes are not known to transmit encephalitis. Encephalitis is usually transmitted by mosquitoes of the Culex genus.


• Yellow Fever (D): Anopheles mosquitoes are not vectors for yellow fever. Yellow fever is primarily transmitted by Aedes mosquitoes.

Therefore, the correct answer is (B) filariasis. Anopheles mosquitoes can spread filariasis, along with their primary role as malaria vectors.

Plants that grow in saline water are called halophytes.
Definition:
- Halophytes are plants that are able to tolerate high levels of salt in their environment.
- They have adapted to survive and thrive in saline conditions, including areas near coastlines or saltwater bodies.
Characteristics of halophytes:
- Halophytes have developed various adaptations to cope with high salt concentrations, such as salt glands or salt-excreting structures.
- They can absorb and store salt in their tissues or excrete it through specialized structures.
- Some halophytes can accumulate salt in their leaves, allowing them to extract freshwater from the surrounding soil.
- They often have shallow root systems to access water near the surface, as deep groundwater may also be saline.
- Halophytes may have succulent leaves or stems to store water and reduce water loss through evaporation.
- They can also have a higher tolerance for drought, as saline environments are often arid.
Examples of halophytes:
- Mangroves: These salt-tolerant trees and shrubs grow in coastal areas and estuaries, where they form dense forests and provide important habitat for various species.
- Salt marsh plants: These include grasses, sedges, and other herbaceous plants that thrive in saline marshes and wetlands.
- Salicornia: Also known as "saltwort" or "pickleweed," Salicornia is a genus of succulent halophytes that are often found in salt marshes and coastal areas.
- Suaeda: This genus of plants includes various halophytic species found in saline habitats, such as coastal dunes and salt flats.
In conclusion, halophytes are a unique group of plants that have adapted to grow and survive in saline water environments. Their ability to tolerate high salt concentrations and thrive in such conditions is a fascinating example of nature's adaptability.

Pyorrhoea, or periodontal disease, to give it a proper medical term, is a disease of the gums, it is one of the most widely prevalent diseases. It affects the membrane surrounding the roots of the teeth and leads to loosening of the teeth, pus formation, and shrinkage of the gum. This disease is the primary cause for tooth loss among adults.

Cholera causes due to bacteria Vibrio comma.