Test: Biology - 12 - NEET MCQ

Axile placentation is not found in Cruciferae.
The axile placentation refers to the arrangement of ovules within the ovary. In this type of placentation, the placenta or the tissue bearing the ovules is located along the central axis of the ovary. The ovules are attached to the placenta, and the ovary is divided into separate chambers or locules.
Explanation:
Cruciferae, also known as the Brassicaceae family, includes plants such as mustard, cabbage, and broccoli. These plants exhibit parietal placentation, where the ovules are attached to the walls or parietes of the ovary. This is different from axile placentation, where the ovules are attached to the central axis.
On the other hand, axile placentation is found in the following families:
- Solanaceae: This family includes plants like tomato, potato, and bell pepper.
- Liliaceae: This family includes plants like lilies, tulips, and onions.
- Malvaceae: This family includes plants like hibiscus and okra.
Therefore, the correct answer is D: Cruciferae, as axile placentation is not found in this family.

Explanation:
Funaria is a type of moss that exhibits alternation of generations, meaning it has both a gametophyte and a sporophyte stage in its life cycle. In Funaria, the sporophyte is not entirely independent of the gametophyte, but it does have some parasitic characteristics.
Key Points:
- Funaria has a dominant gametophyte stage, which is the haploid stage of the moss.
- The gametophyte stage of Funaria is the leafy, green structure that we typically associate with moss.
- The gametophyte produces both male and female gametes through mitosis.
- Fertilization occurs when sperm from the male gametophyte reaches the female gametophyte.
- After fertilization, the diploid zygote develops into the sporophyte stage, which is dependent on the gametophyte.
- The sporophyte of Funaria grows as a stalk-like structure called a seta, which is attached to the gametophyte.
- The sporophyte consists of a capsule at the top, which contains spores.
- The spores are released from the capsule and can develop into new gametophytes under suitable conditions.
- However, the sporophyte of Funaria relies on the gametophyte for nutrients and support, making it a partial parasite.
Conclusion:
In Funaria, the sporophyte is a partial parasite over the gametophyte. While it is not completely independent, it does have some parasitic characteristics by relying on the gametophyte for nutrients and support.

Explanation:
Lathyrus aphaca is a plant species that belongs to the Fabaceae family. It is commonly known as the yellow pea or yellow vetchling. In this plant species, the tendril represents the modification of the leaf.
Reasoning:
- Tendrils are specialized structures that help climbing plants to attach and support themselves on other objects.
- In Lathyrus aphaca, the tendrils are slender, coiled structures that arise from the axils of the leaves.
- They are modified leaf structures that have lost their primary function of photosynthesis.
- Tendrils are highly sensitive to touch and have the ability to coil around objects for support.
- This modification allows the plant to climb and grow vertically, maximizing its exposure to sunlight and reducing competition for resources.
- Therefore, in Lathyrus aphaca, the tendril represents the modification of the leaf.
Conclusion:
The tendril in Lathyrus aphaca represents the modification of the leaf. It is a specialized structure that helps the plant climb and attach itself to other objects for support. This modification allows the plant to grow vertically and optimize its exposure to sunlight.

In Whitlaker’s five kingdom system of classification, multicellular eukaryotes were assigned to:
B: Four of the five kingdoms
Explanation:
- Whitlaker’s five kingdom system of classification was proposed by Robert H. Whitaker in 1969.
- It categorized all living organisms into five kingdoms based on their characteristics and evolutionary relationships.
- The five kingdoms in Whitlaker’s system are: Monera, Protista, Fungi, Plantae, and Animalia.
- Multicellular eukaryotes, which are organisms made up of multiple cells and have a true nucleus, were assigned to four of the five kingdoms in this system.
- The four kingdoms that include multicellular eukaryotes are: Fungi, Plantae, Animalia, and Protista.
- Monera, which includes bacteria and blue-green algae, is the only kingdom in which multicellular eukaryotes are not included.
- Therefore, the correct answer is B: Four of the five kingdoms.

Explanation:
The endodermis is a specialized layer of cells found in the roots of plants. It surrounds the vascular tissue and acts as a selective barrier, controlling the movement of water and nutrients into the vascular system.
Casparian strip:
- The Casparian strip is a band of suberin, a waxy substance, that is present in the cell walls of the endodermis.
- It is impermeable to water and dissolved minerals, forcing them to enter the vascular system through the selectively permeable cell membranes of the endodermal cells.
Passage cells:
- Passage cells are specialized cells found in the endodermis.
- They have thin cell walls and large air spaces, allowing for the movement of gases through the root.
Fusiform initials:
- Fusiform initials are a type of meristematic cell found in the vascular cambium, which is located in the stem and root of plants.
- They are responsible for the production of new vascular tissue, including xylem and phloem.
- While they play a crucial role in plant growth and development, they are not directly related to the endodermis.
Starch sheath:
- The starch sheath is a layer of cells found in the roots of some plants.
- It is located just outside the endodermis and is involved in the storage of starch.
- It helps to regulate the movement of nutrients into the vascular system.
Therefore, the correct answer is C: fusiform initials.

Explanation:
The fertile glume is a specialized bract found at the base of the flower in cereals and grasses. It plays an important role in the reproduction and development of these plants. Let's break down the options given and understand why the answer is D.
A: barren:
- Barren means not able to produce offspring or lacking fertility.
- The fertile glume is actually involved in reproduction, so it cannot be called barren.
- Therefore, option A is incorrect.
B: barsen:
- Barsen does not exist as a term or word.
- Therefore, option B is incorrect.
C: palea:
- The correct term for the fertile glume found at the base of the flower of cereals and grasses is the palea.
- The palea is a specialized bract that protects the flower and aids in pollination and seed development.
- Therefore, option C is the correct answer.
D: none of these:
- This option is incorrect because the correct answer is option C - palea.
In conclusion, the correct term for the specialized bract found at the base of the flower of cereals and grasses is the palea.

Gram-negative bacteria are stained with safranin.
Explanation:
Gram staining is a differential staining technique that is commonly used to classify bacteria into two groups: Gram-positive and Gram-negative. It involves the use of multiple dyes to stain bacterial cells and helps in the identification of different types of bacteria based on their cell wall structure.
Gram-negative bacteria have a thinner peptidoglycan layer in their cell wall, which is surrounded by an outer membrane. This outer membrane makes it difficult for certain dyes to penetrate the cell wall.
Safranin is the counterstain used in the Gram staining technique. It is a red dye that is used to stain the Gram-negative bacteria after the initial staining with crystal violet. Safranin stains the Gram-negative bacteria red or pink, allowing them to be differentiated from the Gram-positive bacteria, which retain the crystal violet stain and appear purple.
In summary, Gram-negative bacteria are stained with safranin, which helps in differentiating them from Gram-positive bacteria during the Gram staining process.

The correct answer is A: production of flowers on old stem.
Explanation:
Cauliflory refers to the production of flowers on old stems. It is a botanical phenomenon where flowers are produced directly on the main trunk or branches of a plant, rather than at the tips of young branches.
Here is a detailed explanation of the options given:
A: Production of flowers on old stem
- Cauliflory refers to the production of flowers on old stems.
- This is a unique adaptation seen in some plants where flowers emerge directly from the main trunk or larger branches.
- Examples of plants that exhibit cauliflory include cacao trees and durian trees.
B: Production of flowers on young branches
- This option is incorrect as cauliflory refers to the production of flowers on old stems, not young branches.
C: Plant which produces cauliflower
- This option is incorrect as cauliflory does not specifically refer to plants that produce cauliflower.
- Cauliflower is a vegetable that is derived from certain varieties of the Brassica oleracea species.
D: Flowers in clusters
- While cauliflory can result in flowers being produced in clusters on the trunk or branches, this option does not accurately describe the phenomenon.
In summary, cauliflory refers to the production of flowers on old stems, making option A the correct answer.

Gametangial copulation is common in Zygomycetes.
Zygomycetes are a class of fungi that reproduce sexually through a process called gametangial copulation. This mode of reproduction involves the fusion of two specialized structures called gametangia, which are produced by different mating types of the fungi. Here is a detailed explanation of gametangial copulation in Zygomycetes:
1. Definition:
- Gametangial copulation is a sexual reproduction process in fungi where two specialized structures called gametangia fuse together to form a zygospore.
2. Gametangia:
- Zygomycetes have two distinct types of gametangia: (+) and (-).
- The (+) gametangia produce nonmotile gametes called (+) gametes.
- The (-) gametangia produce nonmotile gametes called (-) gametes.
3. Gametangial Fusion:
- When the (+) and (-) gametangia of compatible mating types come into close proximity, they undergo fusion.
- The fusion of gametangia is facilitated by the formation of a conjugation tube, which connects the gametangia.
4. Plasmogamy:
- During the fusion of gametangia, the cytoplasm of the (+) and (-) gametes mix together, resulting in a process called plasmogamy.
- Plasmogamy leads to the formation of a multinucleate structure called a zygote or zygospore.
5. Zygospore Formation:
- The multinucleate zygote undergoes a series of developmental changes, leading to the formation of a thick-walled structure called a zygospore.
- The zygospore is a dormant stage that allows the fungus to survive adverse conditions.
6. Meiosis and Germination:
- Inside the zygospore, meiosis occurs, resulting in the formation of haploid spores.
- These spores are released when the zygospore germinates, allowing for the dispersal of the fungus and the initiation of a new life cycle.
In conclusion, gametangial copulation is a common mode of sexual reproduction in Zygomycetes. This process involves the fusion of gametangia, resulting in the formation of a zygospore. The zygospore undergoes meiosis and germination, leading to the production of haploid spores and the continuation of the fungal life cycle.

Explanation:
A fruit that develops from bicarpellary, syncarpous, one chambered ovary and dehisces by one suture only is known as a follicle.
Characteristics of a follicle fruit:
- Bicarpellary: The ovary of the flower is composed of two carpels.
- Syncarpous: The carpels are fused together to form a single structure.
- One chambered ovary: The ovary has only one chamber or cavity.
- Dehisces by one suture only: The fruit opens along one suture or seam to release the seeds.
Examples of follicle fruits:
- Milkweed (Asclepias syriaca): The milkweed fruit is a follicle that contains numerous seeds attached to silky hairs.
- Magnolia (Magnolia grandiflora): The magnolia fruit is a follicle that releases red seeds when mature.
- Delonix regia (Gulmohar): The Gulmohar fruit is a follicle that splits open to release its seeds.
Other types of fruits:
- Capsule: A dry fruit that dehisces to release the seeds through multiple sutures or pores.
- Legume: A dry fruit that usually splits along two sutures, releasing the seeds.
- Siliqua: A long, narrow fruit that dehisces along two sutures and contains seeds attached to a central partition.
Therefore, the correct answer is C: follicle.

The distinguishing feature of family Solanaceae is torsion of carpels.
Explanation:
- The family Solanaceae, also known as the nightshade family, is a family of flowering plants.
- One of the distinguishing features of this family is the torsion of carpels.
- Carpels are the female reproductive organs of a flower, and torsion refers to the twisting or rotation of these carpels.
- In Solanaceae, the carpels undergo torsion, which means they twist or rotate during development.
- This characteristic is unique to the Solanaceae family and helps in identifying plants belonging to this family.
- Torsion of carpels is an important feature in the classification and identification of plant families.
- It is important to note that the other options mentioned (valvate aestivation, basifixed anther, formation of replum by outgrowth of placentae) are not specific to the Solanaceae family and can be found in other plant families as well.

The wood of Pinus is pycnoxylic and monoxylic.
Explanation:
- Pinus is a genus of coniferous trees commonly known as pine trees.
- Pycnoxylic refers to wood with a dense and compact structure, while monoxylic refers to wood with a single primary xylem cylinder.
- Pinus wood exhibits both of these characteristics.
- The wood of Pinus trees is known for its density and strength, making it suitable for various applications such as construction, furniture, and paper production.
- The wood is composed of tracheids, which are elongated cells that form the xylem tissue responsible for water and mineral transport.
- Pinus wood has a distinct growth pattern with annual growth rings, which can be seen when the wood is cut or observed under a microscope.
- The presence of growth rings indicates the monoxylic nature of the wood, as each ring represents a year of growth.
- These growth rings are formed by the differential growth rate of the xylem cells during different seasons.
- The dense and compact structure of Pinus wood contributes to its strength and durability, making it highly valued in various industries.

Definition of Caryopsis:
A caryopsis is a type of fruit that is characteristic of grasses and cereal crops. It is a one-seeded fruit in which the fruit wall and seed coat are fused together, making it difficult to separate them.
Explanation of the answer choices:
A:

that dehisces to expose seeds

- Dehiscence refers to the splitting or opening of a fruit to release its seeds. However, a caryopsis does not dehisce; instead, it remains intact.
B:

that does not have fruit wall

- This statement is incorrect. A caryopsis does have a fruit wall, but it is fused with the seed coat.
C:

which is fleshy and contains many seeds

- This statement is incorrect. A caryopsis is not fleshy; it is dry and hard.
D:

in which fruit wall and seed coat have fused

- This statement is correct. A caryopsis is characterized by the fusion of the fruit wall and seed coat, making it difficult to separate them.
Conclusion:
The correct answer is D:

in which fruit wall and seed coat have fused

. A caryopsis is a fruit in which the fruit wall and seed coat are fused together, distinguishing it from other types of fruits.

Periderm does not contain:

• Phloem: Periderm is a protective tissue that replaces the epidermis in older stems and roots. It is composed of three layers: phellem (cork), phellogen (cork cambium), and phelloderm. Phloem, on the other hand, is a vascular tissue responsible for the transport of organic nutrients in plants. It is found in the inner layers of the stem and root, but not in the periderm.

Components of periderm:

• Phellem: Also known as cork, phellem is the outermost layer of periderm. It is dead, compactly arranged, and provides protection against mechanical injury, water loss, and pathogens.


• Phellogen: Also called cork cambium, phellogen is a meristematic tissue that develops in the cortex or secondary phloem. It produces both phellem (to the outside) and phelloderm (to the inside).


• Phelloderm: Phelloderm is the innermost layer of periderm. It is living tissue that functions in storage and wound healing.

To summarize, periderm does not contain phloem. It consists of phellem, phellogen, and phelloderm as its components.

The character common between cyathium and hypanthodium inflorescence is:
Unisexuality:
- Both cyathium and hypanthodium inflorescences are characterized by having unisexual flowers.
- Unisexuality means that the flowers in these inflorescences are either male or female, but not both.
Explanation:
- Cyathium inflorescence is found in plants of the genus Euphorbia, and it consists of a cup-like structure called a cyathium, which contains multiple unisexual flowers.
- Hypanthodium inflorescence is found in plants of the genus Ficus, and it consists of a hollow, urn-shaped structure called a syconium, which contains numerous tiny unisexual flowers.
Other options:
- Sessile flowers: Sessile flowers are those that do not have a stalk or pedicel and are directly attached to the plant. While both cyathium and hypanthodium inflorescences may have sessile flowers, it is not a character that is common to both.
- Involucre: An involucre is a whorl of bracts that surrounds or encloses a flower or inflorescence. While both cyathium and hypanthodium inflorescences may have an involucre, it is not a character that is common to both.
Therefore, the correct answer is C: Unisexuality. Both cyathium and hypanthodium inflorescences share the character of having unisexual flowers.

Endosperm of Pinus is haploid.
Explanation:
- The endosperm is a tissue found in the seeds of flowering plants. It provides nutrients to the developing embryo.
- In Pinus, the endosperm is formed after fertilization and is derived from the fusion of a haploid male gametophyte (pollen) with a haploid female gametophyte (egg) within the ovule.
- The male gametophyte contains two haploid nuclei, which are involved in fertilization. One of the nuclei fuses with the egg to form the zygote, while the other fuses with the two polar nuclei in the female gametophyte to form the endosperm.
- Since both the male and female gametophytes in Pinus are haploid, the endosperm that is formed is also haploid.
- This haploid endosperm provides nourishment to the developing embryo until it matures into a seed.
- It is worth noting that the endosperm of most flowering plants is typically triploid, resulting from the fusion of one sperm nucleus with two polar nuclei. However, in Pinus, the endosperm is haploid, which is a unique characteristic of gymnosperms, the group to which Pinus belongs.

Explanation:
A fern differs from a moss in having an independent sporophyte. Here is a detailed explanation of why this is the correct answer:
Moss:
- Mosses have a dominant gametophyte generation, which is the part of the life cycle that produces the gametes (sex cells).
- The gametophyte generation of mosses is small, leafy, and photosynthetic.
- The sporophyte generation of mosses is dependent on the gametophyte and grows out of it.
- The sporophyte of mosses consists of a stalk (seta) and a capsule (sporangium) at the top, which produces spores.
Fern:
- Ferns have a dominant sporophyte generation, which is the part of the life cycle that produces the spores.
- The sporophyte generation of ferns is larger, more complex, and photosynthetic.
- The gametophyte generation of ferns is independent of the sporophyte and is much smaller and less conspicuous.
- The gametophyte of ferns produces the gametes (eggs and sperm) in separate structures called archegonia and swimming antherozoids, respectively.
Key Differences:
- Mosses have a dominant gametophyte generation, while ferns have a dominant sporophyte generation.
- Mosses have a dependent sporophyte that grows out of the gametophyte, while ferns have an independent sporophyte.
- Mosses do not have archegonia or swimming antherozoids, which are structures involved in sexual reproduction in ferns.
Therefore, the correct answer is D: an independent sporophyte.

Intercalary Meristem Results in Primary Growth
Primary growth refers to the increase in length of a plant. Intercalary meristem is a type of meristem located at the base of the leaves or internodes of a plant. It is responsible for the growth and elongation of plant organs. The intercalary meristem plays a crucial role in primary growth by adding new cells to the plant body.
Here are the reasons why intercalary meristem results in primary growth:
1. Cell Division:
- Intercalary meristem actively undergoes cell division, leading to the formation of new cells.
- This cell division occurs at the base of the leaves or internodes, allowing for the elongation of the plant organs.
2. Elongation of Plant Organs:
- As the intercalary meristem continuously produces new cells, these cells elongate, leading to the elongation of plant organs.
- This elongation results in primary growth, as the length of the plant increases.
3. Formation of New Tissues:
- The intercalary meristem produces new cells that differentiate into various types of tissues, such as xylem, phloem, and epidermis.
- These new tissues contribute to the primary growth of the plant by adding structural support and facilitating the transport of water, nutrients, and other substances.
4. Role in Regeneration:
- Intercalary meristem also plays a significant role in the regeneration of damaged or removed plant organs.
- When plant organs are damaged or removed, the intercalary meristem can initiate cell division and produce new cells to replace the lost or damaged tissue.
Therefore, the intercalary meristem is responsible for primary growth in plants by promoting cell division, elongation of plant organs, formation of new tissues, and regeneration of damaged or removed plant organs.

Commercially useful cork is obtained from:
- Qurcus suber: This is the correct answer. The cork oak tree (Qurcus suber) is the primary source of commercially useful cork. The bark of the cork oak tree is harvested to obtain cork, which is used in various industries, including wine bottle stoppers, flooring, insulation, and more.
- Tectona grandis: This is incorrect. Tectona grandis is the scientific name for teak, which is a tropical hardwood tree. Teak is not used for cork production.
- Cedrus deodara: This is incorrect. Cedrus deodara, also known as the deodar cedar, is a coniferous tree native to the Himalayas. It is not used for cork production.
- Morus alba: This is incorrect. Morus alba is the scientific name for the white mulberry tree, which is primarily cultivated for its leaves as a food source for silkworms. It is not used for cork production.
Therefore, the correct answer is A: Qurcus suber. Commercially useful cork is obtained from the bark of the cork oak tree.

Electron carriers involved in photophosphorylation are located in the thylakoid membranes of the chloroplast.
Photophosphorylation is the process of converting light energy into chemical energy in the form of ATP. It occurs in the thylakoid membranes of the chloroplast, specifically in the photosystem I and photosystem II complexes. These complexes contain several electron carriers that play a crucial role in the process.
The electron carriers involved in photophosphorylation include:
1. Photosystem II: This protein complex is located in the thylakoid membrane and is responsible for capturing light energy and initiating the electron transport chain. It contains several electron carriers, including plastoquinone (PQ), pheophytin, and the oxygen-evolving complex (OEC).
2. Cytochrome b6f complex: This complex is also located in the thylakoid membrane and serves as an electron transporter between photosystem II and photosystem I. It contains several electron carriers, including cytochrome b6, cytochrome f, and plastocyanin.
3. Photosystem I: This protein complex is located in the thylakoid membrane and receives electrons from the cytochrome b6f complex. It contains several electron carriers, including ferredoxin and ferredoxin-NADP+ reductase.
4. ATP synthase: Although not an electron carrier, ATP synthase is an enzyme complex located in the thylakoid membrane responsible for synthesizing ATP from ADP and inorganic phosphate (Pi) using the energy generated by the electron transport chain.
In summary, the electron carriers involved in photophosphorylation are located in the thylakoid membranes of the chloroplast, specifically in photosystem II, the cytochrome b6f complex, photosystem I, and ATP synthase.

Decline in quantum yield noticed by Emerson:
- Emerson observed a decline in quantum yield, which refers to the efficiency of a process that produces photons.
- Quantum yield is typically measured by the ratio of the number of photons emitted to the number of photons absorbed.
- Emerson's observation suggests that there was a decrease in the number of photons emitted compared to the number of photons absorbed.
Wavelength of the observed decline:
- Emerson noticed the decline in quantum yield at a specific wavelength.
- The wavelength at which the decline was observed is the key factor in determining the answer.
Possible wavelength options:
A: 400-450 nm
B: 600-650 nm
C: 650-680 nm
D: More than 680 nm
Answer: D
- The correct answer is option D, which states that the decline in quantum yield was observed at a wavelength greater than 680 nm.
- This means that the decline occurred at wavelengths beyond the range specified in options A, B, and C.
Explanation:
- The given information does not provide any specific details about the nature or cause of the decline in quantum yield observed by Emerson.
- However, it does indicate that the decline was noticed at a wavelength beyond 680 nm.
- It is important to note that different substances or processes may exhibit variations in their quantum yield at different wavelengths.
- Further research and investigation would be required to determine the exact reasons for the observed decline and its implications.

Answer:
Photosynthesis:
Photosynthesis is the process by which plants, algae, and some bacteria convert light energy into chemical energy in the form of glucose. It occurs in the chloroplasts of plant cells and involves two main stages: the light-dependent reactions and the light-independent reactions (also known as the Calvin cycle).
Production of NADPH:
NADPH (nicotinamide adenine dinucleotide phosphate) is an important molecule in photosynthesis that acts as a reducing agent. It is produced during the light-dependent reactions of photosynthesis, specifically in the process of photophosphorylation.
Types of Photophosphorylation:
Photophosphorylation is the process of converting light energy into chemical energy in the form of ATP and NADPH. There are two types of photophosphorylation: cyclic photophosphorylation and noncyclic photophosphorylation.
1. Cyclic Photophosphorylation:
- Occurs in the thylakoid membrane of chloroplasts.
- Involves only photosystem I (PSI).
- Electrons from the reaction center of PSI are excited by light energy and passed along an electron transport chain.
- The electrons are then returned to PSI, resulting in the production of ATP through chemiosmosis.
- No NADPH is produced in cyclic photophosphorylation.
2. Noncyclic Photophosphorylation:
- Also occurs in the thylakoid membrane.
- Involves both photosystem I and photosystem II (PSII).
- Light energy is absorbed by PSII, exciting electrons in the reaction center.
- These electrons are passed along an electron transport chain and eventually transferred to PSI.
- The excited electrons in PSI are then used to reduce NADP+ to NADPH.
- ATP is also produced through chemiosmosis during this process.
Conclusion:
NADPH is produced during noncyclic photophosphorylation, which involves both photosystem I and photosystem II. This process occurs in the thylakoid membrane of chloroplasts during the light-dependent reactions of photosynthesis.

Action Spectrum of Photosynthesis
The action spectrum of photosynthesis refers to the range of wavelengths of light that are most effective in driving the process of photosynthesis. It was first studied by Engelmann in the late 19th century.
Engelmann's Experiment
In his experiment, Engelmann used a filamentous alga called Spirogyra and a prism to split white light into its constituent colors. He placed the alga under the microscope and exposed it to different wavelengths of light.
Results
Engelmann observed that the alga produced the highest amount of oxygen bubbles (indicating high photosynthetic activity) when exposed to red and blue light. In contrast, green light resulted in very little or no oxygen production.
Interpretation
Based on his findings, Engelmann concluded that red and blue light are the most effective in driving photosynthesis, while green light is least effective. This led to the development of the action spectrum of photosynthesis, which shows the relative effectiveness of different wavelengths of light in promoting photosynthesis.
Significance
The action spectrum of photosynthesis is crucial in understanding the pigments involved in capturing light energy and driving the process of photosynthesis. It helps in identifying the optimal conditions for photosynthesis and has practical applications in agriculture and horticulture.
Therefore, it can be concluded that Engelmann was the first scientist to study and establish the action spectrum of photosynthesis.

Electron acceptors in ETS in mitochondria are arranged according to increasing positive potential.
The electron transport chain (ETS) is a series of electron acceptors and donors located in the inner mitochondrial membrane. These electron acceptors are arranged in a specific order, which allows for the efficient transfer of electrons and the generation of ATP.
Here is a detailed explanation of how electron acceptors are arranged in the ETS:
1. NADH Dehydrogenase Complex: The ETS begins with NADH dehydrogenase complex, also known as Complex I. This complex accepts electrons from NADH, which is produced during the Krebs cycle. The electrons are then transferred to the next electron acceptor.
2. Ubiquinone: Ubiquinone, also known as Coenzyme Q, is a mobile electron carrier. It accepts electrons from Complex I and transfers them to Complex III. Ubiquinone has a relatively low positive potential.
3. Cytochrome b-c1 Complex: Complex III, also known as cytochrome b-c1 complex, accepts electrons from ubiquinone. It contains cytochromes and iron-sulfur proteins that facilitate electron transfer. The positive potential of Complex III is slightly higher than that of ubiquinone.
4. Cytochrome c: After Complex III, the electrons are transferred to cytochrome c, a small soluble protein located in the intermembrane space. Cytochrome c carries the electrons to the next electron acceptor.
5. Cytochrome oxidase Complex: Finally, the electrons are transferred to Complex IV, also known as cytochrome oxidase complex. This complex contains cytochromes and copper ions that facilitate the final transfer of electrons to molecular oxygen, producing water. Complex IV has the highest positive potential among all the electron acceptors in the ETS.
In summary, the electron acceptors in the ETS in mitochondria are arranged according to increasing positive potential. This arrangement ensures the efficient flow of electrons and the generation of ATP through oxidative phosphorylation.

The correct answer is D: Cyt c
- Cytochrome is a protein that contains a heme group and plays a crucial role in electron transfer reactions in cells.
- During terminal oxidation, electrons are transferred from reduced cytochrome to oxygen, resulting in the formation of water.
- The cytochromes involved in electron transfer to oxygen are called cytochrome c oxidases.
- Cytochrome c is a small soluble protein that acts as an electron carrier between the cytochrome b-c1 complex and cytochrome c oxidase.
- It shuttles electrons from the cytochrome b-c1 complex to cytochrome c oxidase, which then transfers the electrons to oxygen.
- Cytochrome c oxidase, also known as complex IV, is the terminal enzyme of the electron transport chain in mitochondria.
- It is responsible for the final step in oxidative phosphorylation, where electrons are transferred from cytochrome c to oxygen, resulting in the production of water.
- Therefore, the cytochrome that hands over electrons to oxygen during terminal oxidation is Cyt c.

What will be zero in a fully turgid cell?
Answer: C. S.P. (Solute Potential)
Explanation:
In a fully turgid cell, the solute potential (S.P.) will be zero. Here's a detailed explanation:
1. Turgor Pressure (T.P.)
- Turgor pressure is the pressure exerted by the fluid inside the cell against the cell wall.
- It is responsible for maintaining the cell's shape and providing support.
- In a fully turgid cell, the T.P. is at its maximum because the cell is fully swollen with water.
- Therefore, T.P. is not zero in a fully turgid cell.
2. Water Potential (W.P.)
- Water potential is the potential energy of water in a system relative to pure water.
- It is influenced by factors such as pressure potential and solute potential.
- In a fully turgid cell, the W.P. is positive as water is present in abundance.
- Therefore, W.P. is not zero in a fully turgid cell.
3. Solute Potential (S.P.)
- Solute potential is a component of water potential and is determined by the concentration of solutes in a solution.
- It represents the tendency of water to move from an area of high water potential to an area of low water potential.
- In a fully turgid cell, there is no net movement of water as the cell is already filled with water.
- Consequently, the S.P. is zero in a fully turgid cell.
4. Osmotic Pressure (O.P.)
- Osmotic pressure is the pressure required to prevent the movement of water across a semipermeable membrane.
- It is directly proportional to the solute concentration of a solution.
- In a fully turgid cell, there is no net movement of water, so the O.P. is negligible.
- However, the O.P. is not necessarily zero in a fully turgid cell.
In conclusion, the solute potential (S.P.) will be zero in a fully turgid cell.

Root pressure is maximum when:
There are four options given, and we need to determine which one is correct.
Option A: Tranpiration is high and absorption is low
This option suggests that root pressure is maximum when transpiration is high and absorption is low. However, this is not the case. Root pressure is actually reduced when transpiration is high because water is being lost through the leaves faster than it can be absorbed by the roots.
Option B: Transpiration is very low and absorption is high
This option suggests that root pressure is maximum when transpiration is very low and absorption is high. This is the correct answer. When transpiration is low, water loss from the leaves is minimal, allowing water to accumulate in the xylem vessels and creating pressure. At the same time, when absorption is high, roots are actively taking in water from the soil, leading to an increased pressure in the xylem.
Option C: Both are very high
This option suggests that root pressure is maximum when both transpiration and absorption are very high. However, this is not the case. As mentioned earlier, root pressure is reduced when transpiration is high, so it cannot be maximum when both transpiration and absorption are very high.
Option D: Both are very low
This option suggests that root pressure is maximum when both transpiration and absorption are very low. However, this is also not the case. When both transpiration and absorption are low, there is minimal movement of water through the plant, resulting in low root pressure.
In conclusion, the correct answer is Option B: Transpiration is very low and absorption is high.