2024 GS Paper I, all questions

UPSC Prelims 2024 · GS Paper I

Question 18: Environment and Ecology

Consider the following :

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

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

aOnly two
bOnly three
cOnly four
dAll five

AnswerUPSC’s answer is (b).

A parasitoid lays its eggs on or in a host; the larvae feed on the host and eventually kill it. Parasitoid species occur among wasps (ichneumonid and braconid wasps), flies (tachinid flies) and some carabid beetles, whose larvae feed on other insects. Centipedes are predators and termites are social wood and detritus feeders, so neither has parasitoids. The count is three.

  • 1. Some carabid beetles have parasitoid larvae that feed on other insects.
  • 2. Centipedes are predators, not parasitoids.
  • 3. Many flies, such as tachinids, are parasitoids.
  • 4. Termites feed on wood and detritus and have no parasitoid species.
  • 5. Many wasps, such as ichneumonids, are parasitoids.

How you could have got this

No shortcut here: in a “how many” question, ruling out options doesn’t help. Every statement has to be judged.

Which options go is worked out from UPSC’s key and the options, not by a model.

Why each option is right or wrong
  • (a) Wrong: three kinds, carabid beetles, flies and wasps, have parasitoid species.
  • (b) Right: carabid beetles, flies and wasps include parasitoid species.
  • (c) Wrong: centipedes and termites have no parasitoid species.
  • (d) Wrong: centipedes and termites are not parasitoids.

Answer: UPSC’s key. Explanation: written by UPSC Grade, not by UPSC.

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Source: UPSC, Civil Services (Preliminary) Examination 2024, General Studies Paper I, Series A. The paper on upsc.gov.in.