Fishes and other aquatic animals use gills to breathe, and they generally have a single-loop circulatory system. Beginning with the heart, what is the order of organs through which blood flows in these animals?
A. heart → gill capillaries → body capillaries → heart
B. heart → gill capillaries → heart → body capillaries → heart
C. heart → body capillaries → gill capillaries → heart
D. heart → body capillaries → heart → gill capillaries → heart