Which of the following statement(s) is/are correct regarding respiratory system of cockroach ?
  1. It consists of a network of trachea, that open through 12 pairs of small holes called spiracles present on the lateral side of the body.
  2. Thin branching tubes carry oxygen from the air to all the parts.
  3. The opening of the spiracles is regulated by sphincters.
  4. Exchange of gases take place at the tracheoles by diffusion.

A. Only (i)

B. (i), (ii) and (iii)

C. (ii), (iii) and (iv)

D. All of these

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