Birds Generate a Lot of Heat, Especially During Flight

Multiple Choice

Birds generate a lot of heat, especially during flight. Yet the adipose tissue under their skin and the feathers atop their skin make it difficult to eliminate excess heat across the skin. Which of the following alternatives can absorb body heat and eliminate it from the bird most effectively?

A) air in the air sacs
B) lymph in the lymphatic vessels
C) blood in the vessels
D) blood in the heart
E) urine in the bladder