Question

Assertion: In cockroaches, respiratory gases directly comes in contact with various organs of the body.
Reason: Cockroaches do not have respiratory pigment.

• A. Both A and R are true and R is the correct explanation of A.
• B. Both A and R are true but R is not the correct explanation of A.
• C. A is true but R is false.
• D. A and R are false.

Answer 1

The correct option is A Both A and R are true and R is the correct explanation of A.

The blood of cockroach is called haemolymph. It is a fluid connective tissue composed of corpuscules and a colourless fluid called plasma. It does not contain any respiratory pigment and therefore plays no role in respiration.
The respiratory system consists of a network of trachea, that open through 10 pairs of small holes called spiracles present on the lateral sides of the body. Thin branching tubes called trachea carry oxygen from the air to all the parts. The openings of the spiracles are regulated by sphincters. Exchange of gases take place at the tracheoles by diffusion.