Respiration in insects Is called direct because

Options

A. the cells exchange `O_(2)//CO_(2)` directly with the air in the tubes
B. the tissues exchange `O_(2)//CO_(2)` directly with coelomic fluid
C. the tissues exchange `O_(2)//CO_(2)` directly with the air outside thorugh body surface
D. tracheal tubes exchange `O_(2)//CO_(2)` directly with the haemocoel which then exchange with tissues.

Answer

A