Question 1

With reference to plant classification, consider the following statements:

1. Epiphytes are plants that draw a partial amount of their nourishment from a host plant.
2. Parasitic plants utilize specialized sucking roots, known as haustoria, to penetrate their host.
3. The aerial roots of epiphytes are primarily adapted to draw moisture and mineral nutrients from the soil.

How many of the statements given above are correct?

Accepted Answer

Only one. Statement 1 is incorrect. It describes a partial parasite, not an epiphyte. Epiphytes grow on a host plant but do not draw nourishment from it; they only use it for support to get access to light. Statement 2 is correct. Parasites penetrate their host plants using sucking roots called haustoria to draw nourishment. Statement 3 is incorrect. The aerial roots of epiphytes draw moisture from the air, not nutrients from the soil. Their clinging roots are for establishing the plant on the host's branches. Therefore, only one statement is correct.

Question 2

Consider the following pairs:

1. Herb : A plant whose stem is always green and tender.
2. Shrub : A woody perennial with a single well-defined stem.
3. Epiphyte : A plant that draws the whole of its nourishment from a host.
4. Climber : A plant that holds on to support by means of tendrils or hooks.

How many of the pairs given above are correctly matched?

Accepted Answer

Only two pairs. Pair 1 is correctly matched. A herb is defined as a plant with a green and tender stem, typically not exceeding 1 meter in height. Pair 2 is incorrectly matched. A shrub is characterized by its habit of branching from the base, not by having a single well-defined stem, which is a characteristic of a tree. Pair 3 is incorrectly matched. This description fits a total parasite. An epiphyte grows on a host for support to access light but does not draw nourishment from it. Pair 4 is correctly matched. A climber is a plant that climbs up supports using various attachments, including tendrils and hooks. Therefore, only two pairs are correctly matched.

Question 3

Consider the following statements regarding plant types:

Statement-I: The Kannimara teak, with a recorded height of 48.75 meters, cannot be classified as a shrub.
Statement-II: A shrub is defined as a woody perennial plant that is distinguished from a tree by its low stature and its habit of branching from the base.

Which one of the following is correct in respect of the above statements?

Accepted Answer

Both Statement-I and Statement-II are correct and Statement-II is the correct explanation for Statement-I.. Statement-I is correct. The Kannimara teak's height of 48.75 meters far exceeds the maximum height for a shrub. Statement-II is also correct. It provides the definition of a shrub, highlighting its low stature (not more than 6 meters) and branching from the base, which distinguishes it from a tree. Statement-II provides the definitional criteria (specifically, the low stature) that validates Statement-I. Because a shrub cannot be taller than 6 meters, the 48.75-meter-tall Kannimara teak cannot be a shrub. Thus, Statement-II is the correct explanation for Statement-I.

Question 4

Consider the following statements regarding the effect of light on plants:
1. High intensity of light favours shoot growth over root growth, leading to shorter stems and thicker leaves.
2. Plants grown in red light tend to be small and dwarf, whereas those grown in blue light exhibit cellular elongation.
3. All colours within the visible spectrum of light are equally effective in the process of photosynthesis.

Accepted Answer

None. Statement 1 is incorrect. Extremely high light intensity favours root growth rather than shoot growth. Statement 2 is incorrect. Red light results in the elongation of cells, while plants grown in blue light are small. Statement 3 is incorrect. Only red and blue light from the visible spectrum are mentioned as being effective in photosynthesis, not all colours equally.

Question 5

With reference to the effects of abiotic components on plants, consider the following statements:
1. Frost causes plant death by freezing water within the plant's intercellular spaces, which withdraws water from the cells, leading to dehydration and increased salt concentration.
2. High temperatures can lead to the death of a plant by causing the coagulation of its protoplasmic proteins.
3. The widespread death of sal seedlings is primarily caused by the formation of cankers due to frost.

Accepted Answer

Only two. Statement 1 is correct. Frost freezes water in the intercellular spaces, which then withdraws water from the cells. This dehydration and increasing concentration of salts can lead to the death of the plant. Statement 2 is correct. Excessive high temperature results in the death of the plant due to the coagulation of protoplasmic proteins. Statement 3 is incorrect. The death of sal seedlings is attributed to increased transpiration in the morning when their roots, in chilled soil, are unable to supply moisture. While frost can lead to cankers, this is not cited as the main reason for sal seedling death.

Question 6

Consider the following statements:
1. 'Die back' is an adaptive mechanism in plants where the root system progressively dies while the shoot remains alive for several years.
2. Dense overhead canopy and un-decomposed leaf litter are among the potential causes for the 'die back' phenomenon.
3. Tree root networks are primarily responsible for trapping and removing airborne particulate matter such as soot and dust.

Accepted Answer

Only one. Statement 1 is incorrect. 'Die back' is a mechanism where the shoots die, but the root remains alive for years. Statement 2 is correct. The listed causes for die back include dense overhead canopy and un-decomposed leaf litter on the surface. Statement 3 is incorrect. Tree leaves, not root networks, help trap and remove tiny particles of soot and dust from the air. Tree root networks filter contaminants in soils.

Question 7

Consider the following statements regarding the trapping mechanisms of insectivorous plants:
1. Plants with a 'pitfall' mechanism, such as a jar-like structure, are classified as active trappers.
2. Aldrovanda utilizes sensitive trigger hairs, and upon contact, the two halves of its leaf blade close along the midrib to trap prey.
3. In Pinguicula, the entire leaf acts as a trap where insects get stuck in a sticky exudate, followed by the rolling up of the leaf margins.
How many of the statements given above are correct?

Accepted Answer

Only two. Statement 1 is incorrect. Insectivorous plants with a 'pitfall' mechanism are classified as passive types. Active types are those that can close their leaf traps upon contact. Statement 2 is correct. Aldrovanda has sensitive trigger hairs on the leaf midrib, and the leaf blades close along the midrib when an insect makes contact. Statement 3 is correct. In Pinguicula, the entire leaf functions as a trap, using a sticky exudate and the rolling of leaf margins to capture insects.

Question 8

Consider the following statements regarding the habitats of insectivorous plants in India:
1. Nepenthes is primarily found in the alpine heights of the Himalayas, from Kashmir to Sikkim.
2. Aldrovanda, a rootless aquatic plant, occurs in the salt marshes of Sunderbans and also in freshwater bodies.
3. Pinguicula is confined to the high-rainfall hills and plateaus of the north-eastern region of India.
How many of the statements given above are correct?

Accepted Answer

Only one. Statement 1 is incorrect. Pinguicula, not Nepenthes, grows in the alpine heights of the Himalayas. Nepenthes is confined to the high-rainfall hills of the north-eastern region. Statement 2 is correct. Aldrovanda is a free-floating, rootless aquatic plant found in the salt marshes of Sunderbans and also in freshwater bodies like ponds and lakes. Statement 3 is incorrect. Nepenthes, not Pinguicula, is confined to the high-rainfall hills and plateaus of the north-eastern region, particularly the Garo, Khasi, and Jaintia hills.

Question 9

With reference to the nutritional strategy of insectivorous plants, consider the following statements:
1. These plants are typically found in nutrient-rich, well-drained soils where they outcompete normal plants.
2. They hunt insects primarily to supplement their production of carbohydrates, which cannot be met by photosynthesis alone.
3. The acidic, anaerobic conditions of their habitats inhibit microorganisms required for the complete decomposition of organic matter.
How many of the statements given above are correct?

Accepted Answer

Only one. Statement 1 is incorrect. Insectivorous plants are usually associated with rain-washed, nutrient-poor soils or wet, acidic, ill-drained areas. Statement 2 is incorrect. These plants supplement their photosynthetic food production by trapping insects to obtain nitrogen from their nitrogen-rich bodies, not carbohydrates. Statement 3 is correct. The habitats of these plants are often wet and acidic due to anaerobic conditions, which cause partial decomposition of organic matter. These conditions inhibit most microorganisms necessary for complete decomposition.

Question 10

Consider the following statements regarding invasive alien species in India:
1. Black Wattle, introduced for afforestation in the Western Ghats, is native to Tropical South America.
2. Water Hyacinth, an aggressive colonizer of aquatic ecosystems, is native to Tropical Africa.
3. Leptocybe invasa is a tiny wasp that forms leaf and stem galls in Eucalyptus and is considered an invasive fauna.
How many of the statements given above are correct?

Accepted Answer

Only one. Statement 1 is incorrect. Black Wattle is native to South East Australia, not Tropical South America. Statement 2 is incorrect. Water Hyacinth is native to Tropical America, not Tropical Africa. Statement 3 is correct. Leptocybe invasa is described as a tiny wasp, a form of fauna, that creates galls in Eucalyptus, and is an invasive pest in India.

Question 11

Consider the following statements regarding biological invasions:
1. Any species that occurs outside its natural range is, by definition, considered an alien invasive species.
2. The introduction of invasive species invariably leads to a direct and immediate decrease in local species richness due to competition and predation.
3. Biological invasion by alien species is recognized as a major threat to native ecosystems, and its effects are often irreversible.
How many of the statements given above are correct?

Accepted Answer

Only one. Statement 1 is incorrect. Alien species are those outside their natural range, but only those that threaten native plants, animals, or biodiversity are called 'alien invasive species'. Statement 2 is incorrect. Biological invasions can potentially lead to an initial increase in species richness as new species are added to the pool, before extinctions of native species cause a decrease. Statement 3 is correct. Biological invasion is considered a major threat to biodiversity with consequences that are enormous and often irreversible.

Question 12

Consider the following pairs:
1. Palmyra, Toddy Palm : Native to Tropical America
2. Datura, Mad Plant : Invades water courses and seasonally flooded wetlands
3. Black Wattle : Regenerates rapidly after fire
4. Leptocybe invasa : A species of invasive flora
How many of the above pairs are correctly matched?

Accepted Answer

Only two pairs. Pair 1 is incorrectly matched. Palmyra, Toddy Palm is native to Tropical Africa. Pair 2 is correctly matched. Datura, Mad Plant Thorn Apple invades water courses and seasonally flooded wetlands. Pair 3 is correctly matched. Black Wattle regenerates rapidly after fire and forms dense thickets. Pair 4 is incorrectly matched. Leptocybe invasa is an insect (a tiny wasp), which is classified under fauna, not flora.

Question 13

With reference to medicinal plants found in India, consider the following statements:
1. The alkaloid reserpine, found in Sarpagandha, has a depressant action on the central nervous system and is used for its sedative properties.
2. The juice of the Sarpagandha leaves is used as a remedy for opacity of the cornea, while the root extracts are used for treating intestinal disorders.
3. The commercial synthesis of cortisone and progesterone relies on Diosgenin, a steroid sapogenin extracted from the tubers of Sarpagandha.

Accepted Answer

Only two. Statement 1 is correct. Sarpagandha contains the alkaloid reserpine, which has a depressant action on the central nervous system and produces sedation. Statement 2 is correct. The juice of the leaves is used as a remedy for opacity of the cornea, and the root extracts are used for treating intestinal disorders like diarrhoea and dysentery. Statement 3 is incorrect. Diosgenin, which is used for the commercial synthesis of cortisone and other steroid products, is extracted from the tubers of Elephant's foot (Dioscorea wild yam), not Sarpagandha.

Question 14

Consider the following pairs:

Plant : Primary Chemical/Use
1. Beddomes Cycad : Used for rheumatoid arthritis and muscle pains.
2. Kuth : Source of the alkaloid reserpine.
3. Elephant's foot : Commercial source of Diosgenin for steroid synthesis.
4. Indian Podophyllum : Yields an aromatic oil used in perfumery.

How many of the pairs given above are correctly matched?

Accepted Answer

Only two pairs. Pair 1 is correctly matched. The male cones of Beddomes Cycad are used by local herbalists as a cure for rheumatoid arthritis and muscle pains. Pair 2 is incorrectly matched. Kuth roots contain the alkaloid 'saussurine', not reserpine. Reserpine is the principal alkaloid of Sarpagandha. Pair 3 is correctly matched. Elephant's foot is the commercial source of Diosgenin, which is used for the synthesis of cortisone, progesterone, and other steroid products. Pair 4 is incorrectly matched. Indian Podophyllum rhizomes are a source of a toxic resin called podophyllin. It is the roots of Kuth that yield a strongly scented aromatic oil used in perfumery.

Question 15

Consider the following statements regarding certain plant species in India:
1. The pith of the Tree Fern is a source of starch and can be consumed, while regular consumption of starch from Cycads has been linked to a neurological disease.
2. The Blue Vanda orchid is highly valued for producing interspecific hybrids, whereas the Ladies Slipper Orchid is primarily used as a collector's item.
3. Beddomes Cycad is noted for its fire-resistant properties and is distributed in the Eastern Peninsular India, while the Elephant's foot is found throughout the North Western Himalayas.

Accepted Answer

All three. Statement 1 is correct. The pith of the Soft Tree Fern is a good source of starch and can be eaten. Conversely, there is an indication that regular consumption of starch derived from cycads is a factor in the development of a neurological disease. Statement 2 is correct. Blue Vanda is one of the few botanical orchids with blue flowers, a property appreciated for producing hybrids. Ladies Slipper Orchids are mainly used as collector's items. Statement 3 is correct. Beddomes Cycad is found in Eastern Peninsular India and possesses fire-resistant properties. Elephant's foot is distributed throughout the North Western Himalayas.

Question 16

Consider the following statements regarding the internal structure and function of a tree trunk:
1. The phloem, which constitutes the inner layer of bark, is primarily responsible for generating new cells that allow the tree to grow wider each year.
2. The cambium is a layer of living cells whose main job is to carry sap full of sugar from the leaves to the other parts of the tree.
3. Annual rings can be analyzed to determine not only the age of a tree but also past environmental conditions such as water availability.
How many of the statements given above are correct?

Accepted Answer

Only one. Statement 1 is incorrect. The cambium, not the phloem, is the part of the tree that makes new cells, allowing the tree to grow wider. Statement 2 is incorrect. The phloem, which is the inner layer of bark, is responsible for carrying sugar-rich sap from the leaves. The cambium's role is cell division for growth. Statement 3 is correct. The size of a tree's growth rings is determined by environmental conditions like temperature and water availability, making them useful for studying past climates (Paleo-Climatology).

Question 17

Consider the following statements:
Statement I: Deciduous trees are adapted to survive periods of environmental stress by shedding their leaves.
Statement II: In hot and dry climates, deciduous trees typically lose their leaves during the autumn season to prepare for a cold winter.
Statement III: Evergreen trees are characterized by retaining the exact same foliage throughout their entire lifespan, never losing any leaves.
Which one of the following is correct in respect of the above statements?

Accepted Answer

Statement I is correct, but Statement II and Statement III are incorrect.. Statement I is a correct generalization. Deciduous trees shed leaves to cope with stress, such as cold winters or dry seasons. Statement II is incorrect. It conflates adaptations for two different climates. In hot and dry climates, trees lose leaves during the dry season, whereas leaf loss in autumn is characteristic of trees in cold climates preparing for winter. Statement III is incorrect. Evergreen trees do lose their old leaves, but they do so gradually over time and are never completely bare. They do not retain the same foliage indefinitely.

Question 18

Consider the following statements about the anatomy and physiology of trees:
1. The crown of a tree is primarily responsible for collecting water and nutrients from the soil and storing them for future use.
2. Trees possess a biological mechanism to actively restore and repair wood tissue that has been injured or infected.
3. The trunk of a tree provides structural support and facilitates the transport of sugars produced in the leaves to other parts of the organism.
How many of the statements given above are correct?

Accepted Answer

Only one. Statement 1 is incorrect. The function described—collecting water and nutrients from the soil—is performed by the roots, not the crown. The crown's main roles are photosynthesis and transpiration. Statement 2 is incorrect. Trees do not restore or repair injured wood; instead, they compartmentalize the damaged tissue to prevent the spread of decay. Statement 3 is correct. The trunk provides the tree's shape and support and transports water and nutrients up from the soil and sugar down from the leaves.

Question 19

Consider the following pairs:

Invasive Species      : Native Region
1. Black Wattle       : South East Australia
2. Water Hyacinth     : Tropical Africa
3. Prosopis juliflora : Mexico
4. Lantana camara     : Tropical America

How many of the pairs given above are correctly matched?

Accepted Answer

Only three pairs. Pair 1 is correct: Black Wattle is native to South East Australia. It is an invasive species in India's Western Ghats. Pair 2 is incorrect: Water Hyacinth is native to Tropical America, not Tropical Africa. It is a major aquatic weed in India. Pair 3 is correct: Prosopis juliflora (Mesquite) is native to Mexico and parts of Central and South America. Pair 4 is correct: Lantana camara is native to Tropical America and is one of India's most widespread invasive species. Therefore, three pairs are correctly matched.

Question 20

With reference to Invasive Alien Species (IAS), consider the following statements:

1. They are a major driver of biodiversity loss, particularly threatening endemic species.
2. Their successful establishment is often due to the absence of natural predators in the new environment.
3. The introduction of an alien species always results in a net decrease in local species richness from the outset.

How many of the statements given above are correct?

Accepted Answer

Only two. Statement 1 is correct: Biological invasion by IAS is recognized as a major threat to native biodiversity and can lead to the decline and extinction of endemic species. Statement 2 is correct: A primary reason for the proliferation of IAS is that they are introduced into an area where their natural predators, competitors, and pathogens are absent, allowing their populations to grow unchecked. Statement 3 is incorrect: Initially, the introduction of a new species increases the total species count (species richness) in an area. The net decrease occurs over time as the invasive species outcompetes and eliminates native species. The process is not always immediate.

Question 21

With reference to the management of invasive alien species in India, consider the following statements:

1. The Wildlife (Protection) Act, 1972, explicitly lists and prohibits the trade of invasive alien fauna like the Giant African snail.
2. The introduction of Black Wattle for afforestation in the Western Ghats was a planned introduction that later became invasive.
3. The responsibility for preventing the entry of invasive species is primarily managed by the Ministry of Agriculture and Farmers' Welfare through its quarantine regulations.

Which of the statements given above is/are correct?

Accepted Answer

2 and 3 only. Statement 1 is incorrect. The Wildlife (Protection) Act, 1972, has historically focused on the protection of native Indian species and their habitats. It did not contain an explicit list prohibiting invasive alien fauna. While the Wildlife (Protection) Amendment Act, 2022, has introduced provisions empowering the Central Government to regulate invasive alien species, this is a recent development and the statement implies it was an original feature of the Act. The broader legal framework for managing IAS also involves the Environment (Protection) Act, 1986, and the Biological Diversity Act, 2002.

Statement 2 is correct. Black Wattle (Acacia mearnsii) was intentionally introduced in the Western Ghats, particularly in the Nilgiris, for afforestation and commercial purposes such as tannin production. This planned introduction subsequently led to its escape from cultivation, and it has become a major invasive species, outcompeting native flora and altering ecosystem structures, especially in the shola-grassland mosaics.

Statement 3 is correct. The prevention of the entry of alien species, particularly pests, weeds, and pathogens, is a critical biosecurity function. In India, this responsibility is primarily shouldered by the Ministry of Agriculture and Farmers' Welfare. It operates a network of plant and animal quarantine stations at airports, seaports, and land borders to regulate imports and prevent the introduction of potentially harmful and invasive species, as mandated by regulations like the Plant Quarantine (Regulation of Import into India) Order, 2003.

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