The circulatory system of an insect ______.

1. a. is a closed system
2. b. includes a four-chambered heart
3. c. circulates hemolymph
4. d. moves blood through four separate circuits.

Concept introduction: The circulatory system is the organ system that permits blood or body fluids to circulate all over the body for distributing all the essential nutrients and gases all over the body tissues. It varies in different group of animals ranging from an open circulatory system seen in insects composed of hemolymph to a highly systematic closed system in mammalians composed of blood, blood vessels, a definite pumping station and the heart.

Reason for correct answer: All the members of the phylum arthropods possess an open circulatory system where hemolymph is seen to be flowing freely over all body cavities and it makes direct contact with the all major internal organs. This type of circulatory system is known as open. Uptake of essential nutrients and gaseous exchange in this group of organisms are made with the help of this hemolymph. The movement of hemolymph through the entire internal body tissues is maintained by a vessel passing along their dorsal side.

Option c. is given as “circulates hemolymph”. Since insects do not have a closed circulatory system, gaseous exchange and distribution of essential nutrients are done by hemolymph. Therefore, option c. is the correct answer.

Reason for incorrect answer:

Option a. is given as “is a closed system”.

Insects do not have a closed circulatory system rather they have hemolymph, a kind of body fluid that carries all the essential nutrients and exchange gas with every internal tissues...