Biology Archives

41. Night blindness is caused by the deficiency of

Night blindness is caused by the deficiency of

Vitamin C

Vitamin A

Vitamin K

Vitamin B

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UPSC CISF-AC-EXE – 2017

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Night blindness is caused by the deficiency of Vitamin A.

Vitamin A is essential for the formation of rhodopsin, a pigment found in the rod cells of the retina that is crucial for vision in low light conditions. A deficiency leads to impaired night vision (nyctalopia).

Vitamin C deficiency causes Scurvy. Vitamin K deficiency can lead to blood clotting disorders. Deficiencies of various Vitamin B types cause conditions like Beriberi (B1), Pellagra (B3), anemia, etc.

42. Which one among the following is the richest source of vitamin C?

Which one among the following is the richest source of vitamin C?

Apple

Banana

Amla

Papaya

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UPSC CISF-AC-EXE – 2017

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Amla (Indian gooseberry) is considered one of the richest natural sources of vitamin C.

Amla contains an exceptionally high concentration of ascorbic acid (Vitamin C) compared to most other fruits.

While apple, banana, and papaya do contain vitamin C, their levels are significantly lower than that found in Amla. Citrus fruits and guavas are also known for high vitamin C content, but among the options given, Amla is superior.

43. Consider the following : Cashew Papaya Red sanders How many of th

Consider the following :

Cashew
Papaya
Red sanders

How many of the above trees are actually native to India ?

Only one

Only two

All three

None

This question was previously asked in

UPSC IAS – 2024

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Out of the three trees listed, only Red Sanders is native to India.

– Cashew (*Anacardium occidentale*) is native to Brazil and was introduced to India by the Portuguese.
– Papaya (*Carica papaya*) is native to tropical America (southern Mexico and Central America) and was later spread globally.
– Red Sanders (*Pterocarpus santalinus*) is endemic to a specific geographical region in India, namely the Eastern Ghats mountain range in the southern part of the Indian peninsula.

Identifying native species is important for biodiversity conservation and understanding ecological roles. While Cashew and Papaya are now widely cultivated in India, they are not indigenous to the country’s flora. Red Sanders is valued for its rich red wood and is unfortunately listed as ‘Endangered’ by the IUCN due to overexploitation.

44. Consider the following : Butterflies Fish Frogs How many of the a

Consider the following :

Butterflies
Fish
Frogs

How many of the above have poisonous species among them ?

Only one

Only two

All three

None

This question was previously asked in

UPSC IAS – 2024

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All three groups listed – Butterflies, Fish, and Frogs – contain species that are poisonous.

– Butterflies: Some butterfly species, like the Monarch butterfly, are poisonous due to toxins accumulated from their host plants (e.g., milkweed). These toxins make them unpalatable to predators.
– Fish: Many fish species are poisonous if eaten (e.g., pufferfish containing tetrodotoxin). Additionally, many fish are venomous, possessing spines or barbs that deliver toxins (e.g., stonefish, lionfish, stingrays).
– Frogs: Numerous frog species, particularly brightly colored ones in tropical regions (like poison dart frogs), secrete potent toxins through their skin as a defense mechanism. These toxins can be extremely dangerous or even lethal to predators.

The terms “poisonous” (toxic when eaten or touched) and “venomous” (delivers toxin via bite, sting, etc.) are distinct, but both fall under the umbrella of containing toxins for defense or offense. The question asks about “poisonous species,” which generally encompasses both forms of toxicity in common usage, and in this context, species with either type of toxicity are found in all three groups.

45. Consider the following statements : 1. Lions do not have a particular

Consider the following statements :

1. Lions do not have a particular breeding season.

2. Unlike most other big cats, cheetahs do not roar.

3. Unlike male lions, male leopards do not proclaim their territory by scent marking.
Which of the statements given above are correct ?

1 and 2 only

2 and 3 only

1 and 3 only

1, 2 and 3

This question was previously asked in

UPSC IAS – 2024

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Let’s evaluate each statement:
1. Lions do not have a particular breeding season. This statement is generally correct. Lions can breed throughout the year, although the timing of births might be influenced by local conditions such as prey availability, which can lead to peak periods in some areas. However, they are capable of breeding year-round, unlike some animals with strict seasonal breeding.
2. Unlike most other big cats, cheetahs do not roar. This statement is correct. Cheetahs belong to the genus *Acinonyx*, while the roaring big cats (lion, tiger, leopard, jaguar, snow leopard) belong to the genus *Panthera*. Cheetahs vocalize with chirps, purrs, hisses, and growls but lack the anatomical structure (specifically, the hyoid bone structure) that allows true roaring.
3. Unlike male lions, male leopards do not proclaim their territory by scent marking. This statement is incorrect. Leopards, both male and female, are solitary and highly territorial. They actively scent mark their territories using urine, feces, and by rubbing scent glands against objects. Male lions also scent mark, although their territorial behaviour is linked to the pride structure. The statement’s assertion that male leopards *do not* scent mark is false.
Based on the analysis, statements 1 and 2 are correct.

– Lions can breed year-round.
– Cheetahs cannot roar; they chirp, purr, etc.
– Both male lions and male leopards use scent marking to define territory.

The ability to roar is linked to the morphology of the hyoid bone. In roaring cats (*Panthera* genus), the hyoid bone is not fully ossified, allowing for a wider range of vocalization, including roaring. Non-roaring cats, including cheetahs and domestic cats, have a fully ossified hyoid bone and purr instead of roar.

46. Consider the following pairs : Country Animal found in its n

Consider the following pairs :

	Country	Animal found in its natural habitat
1.	Brazil	Indri
2.	Indonesia	Elk
3.	Madagascar	Bonobo

How many of the pairs given above are correctly matched ?

Only one

Only two

All three

None

This question was previously asked in

UPSC IAS – 2024

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Let’s evaluate each pair:
1. Brazil, Indri: The Indri (Indri indri) is the largest living lemur and is found only in Madagascar, not Brazil. Incorrect match.
2. Indonesia, Elk: The term “Elk” usually refers to *Cervus canadensis*, native to North America and East Asia. While some deer species in Indonesia might be colloquially referred to with “elk” in their name (like the Sambar deer or ‘Indian Elk’), the standard “Elk” is not naturally found in Indonesia. Incorrect match.
3. Madagascar, Bonobo: Bonobos (Pan paniscus) are found only in the Congo Basin in Central Africa (Democratic Republic of Congo), not in Madagascar. Incorrect match.
None of the given pairs are correctly matched regarding the natural habitat of the animals.

– Indri are native to Madagascar.
– Bonobos are native to the Democratic Republic of Congo.
– Elk (*Cervus canadensis*) are native to North America and East Asia.

Zoogeography, the study of the geographical distribution of animal species, reveals that different regions of the world have distinct faunas due to evolutionary history, climate, and geographical barriers. Madagascar is famous for its unique biodiversity, including many endemic species of lemurs.

47. The organisms “Cicada, Froghopper and Pond skater” are :

The organisms “Cicada, Froghopper and Pond skater” are :

Birds

Fish

Insects

Reptiles

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UPSC IAS – 2024

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Cicadas, Froghoppers, and Pond skaters are all members of the class Insecta.
– Cicadas are well-known for their noisy songs and belong to the order Hemiptera.
– Froghoppers, also known as spittlebugs, are small insects belonging to the order Hemiptera, superfamily Cercopoidea.
– Pond skaters, also known as water striders, are insects in the family Gerridae, also part of the order Hemiptera, adapted to live on the surface of water.
All three are common examples of insects.

– Cicadas are insects known for sound production.
– Froghoppers are insects known for producing spittle.
– Pond skaters are insects that live on water surfaces.

The order Hemiptera includes a diverse range of insects, often characterized by having piercing-sucking mouthparts. It contains many familiar insects like true bugs, aphids, cicadas, leafhoppers, and scale insects.

48. Consider the following plants : 1. Groundnut 2. Horse-gram 3. Soyb

Consider the following plants :

1. Groundnut
2. Horse-gram
3. Soybean

How many of the above belong to the pea family ?

Only one

Only two

All three

None

This question was previously asked in

UPSC IAS – 2024

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All three plants listed – Groundnut (*Arachis hypogaea*), Horse-gram (*Macrotyloma uniflorum*), and Soybean (*Glycine max*) – belong to the pea family, also known as Fabaceae or Leguminosae. Plants in this family are commonly referred to as legumes and are known for their characteristic pods and ability to fix atmospheric nitrogen through symbiotic relationships with bacteria in root nodules.

The Fabaceae family is one of the largest plant families and includes many economically important crops such as beans, peas, lentils, chickpeas, soybeans, peanuts, and clover.

Legumes are a valuable source of protein and fiber in human diets and play a significant role in agriculture due to nitrogen fixation, which improves soil fertility.

49. Consider the following : 1. Carabid beetles 2. Centipedes 3. Flies

Consider the following :

1. Carabid beetles
2. Centipedes
3. Flies
4. Termites
5. Wasps

Parasitoid species are found in how many of the above kind of organisms ?

Only two

Only three

Only four

All five

This question was previously asked in

UPSC IAS – 2024

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Parasitoid species are found among flies (Order Diptera) and wasps (Order Hymenoptera). Many families within these orders contain species that are parasitoids, with their larvae developing inside or on a host organism, eventually leading to the host’s death. Carabid beetles and Centipedes are typically predatory, while Termites are social insects primarily feeding on wood or other plant material. Therefore, parasitoid species are found in only two of the listed kinds of organisms: Flies and Wasps.

A parasitoid is an organism that lives in close association with a host, where the parasitoid obtains nutrients from the host, eventually resulting in the death of the host. This is distinct from a parasite, which typically does not kill its host.

Examples of parasitoid flies include Tachinid flies, which parasitize other insects. Many families of wasps, such as Ichneumonidae and Braconidae, are well-known for their parasitoid lifestyles, attacking caterpillars, beetles, aphids, and other insects.

50. Which one of the following is synthesised in human body that dilates b

Which one of the following is synthesised in human body that dilates blood vessels and increases blood flow ?

Nitric oxide

Nitrous oxide

Nitrogen dioxide

Nitrogen pentoxide

This question was previously asked in

UPSC IAS – 2024

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The question asks for a substance synthesized in the human body that dilates blood vessels and increases blood flow.
Nitric oxide (NO) is a molecule produced by cells in the endothelium (lining of blood vessels) and other tissues. It is a potent vasodilator, meaning it causes the smooth muscles in the walls of blood vessels to relax, leading to increased diameter and blood flow. This process is crucial for regulating blood pressure and blood flow to different parts of the body.
Nitrous oxide (N₂O), also known as laughing gas, is an anesthetic and analgesic gas used in medicine but is not synthesized in the human body for vasodilation.
Nitrogen dioxide (NO₂) and Nitrogen pentoxide (N₂O₅) are oxides of nitrogen that are primarily environmental pollutants and industrial chemicals, not molecules synthesized endogenously in the human body for physiological functions like vasodilation.
Therefore, Nitric oxide is the correct answer.

Nitric oxide (NO) acts as a signaling molecule in the cardiovascular system, promoting vasodilation by activating guanylate cyclase, which leads to the relaxation of vascular smooth muscle cells. This mechanism is important for regulating blood pressure and tissue perfusion.

NO plays various other roles in the body, including neurotransmission, immune response, and muscle function. The discovery of NO’s role as a signaling molecule in the cardiovascular system was awarded the Nobel Prize in Physiology or Medicine in 1998. Medications like nitroglycerin, used to treat angina (chest pain), work by releasing NO, which dilates coronary arteries. Sildenafil (Viagra) also works by enhancing the effects of NO on blood vessels.