When abdomen expands, the number of spiracles open is_____________?

Correct answer: D. 8

  • A. 2
  • B. 3
  • C. 6
  • D. 8

Explanation

When the cockroach abdomen expands during inspiration, the eight abdominal pairs of spiracles open to admit air. The two thoracic pairs are generally associated with expiration in the usual textbook description. Students often choose two by counting only the thoracic spiracles and overlooking the eight abdominal pairs.

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