2007 General Studies, all questions

UPSC Prelims 2007 · General Studies

Question 114: Science and Technology

How do most insects respire?

aThrough skin
bThrough gills
cBy lungs
dBy tracheal system

AnswerThe answer is (d).

Most insects breathe through a tracheal system: air enters through small openings called spiracles on the sides of the body and passes through branching tubes (tracheae) that carry oxygen directly to the tissues, without the blood doing the carrying. Gills, lungs and skin serve other animals, such as fish, mammals and earthworms.

Why each option is right or wrong
  • (a) Skin breathing is used by animals such as earthworms.
  • (b) Gills are used by aquatic animals such as fish.
  • (c) Lungs are used by vertebrates such as mammals.
  • (d) Correct: insects use a tracheal system.

Explanation: written by UPSC Grade, not by UPSC.

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Source: UPSC, Civil Services (Preliminary) Examination 2007, General Studies. UPSC's own paper isn't online; the words are from a published compilation. The paper on upsc.gov.in.