The respiratory system of insects consists of
A) branched air tubes called spiracles that supply capillaries.
B) branched air tubes called tracheae that supply capillaries.
C) branching gill systems that end in openings called tracheae.
D) branching gill systems that end in openings called spiracles.
E) extensive layers of gas exchange tissue just under the exoskeleton.

Question

Quizplus · Accepted Answer

The respiratory system of insects consists of branched air tubes called tracheae that supply capillaries. These tracheae deliver oxygen directly to tissues and cells through a network of smaller tubes called tracheoles.

Answer: A, D 
 The options C and E are incorrect as insects use tracheae and spiracles for respiration, not gills. Therefore, the correct choices are A for spiracles and D for branching gill systems that end in openings called spiracles.

The Respiratory System of Insects Consists of