Countercurrent heat exchange, a circulatory arrangement in which warm blood leaving the body core passes cooler blood returning from the extremities, allows for heat to pass into regions where little warmth or heat mechanisms exist.

A. little warmth or heat mechanisms exist
B. little warmth or hear mechanisms exists
c. few heat mechanisms and little warmth exists
D. there is little warmth or heat mechanisms available
E. there are few heat mechanixms and little available warmth