An open circulatory system is characterized by
A) the absence of a heart.
B) the absence of blood vessels.
C) blood with a composition different from that of tissue fluid.
D) the absence of capillaries.
E) a higher-pressure circuit through gills than to other organs.

Question

Quizplus · Accepted Answer

An open circulatory system is characterized by the absence of capillaries. In this type of system, the circulatory fluid (hemolymph) bathes the organs directly, and there are no distinct blood vessels. Hemolymph is pumped through a series of sinuses, or open spaces, where it bathes the organs before returning to the heart.

An Open Circulatory System Is Characterized by