Bumblebees show some ability to control their
 own body temperature. During cold weather,
 bumblebees have been observed warming their
 flight muscles by shivering. The bees are able to
 maintain a body temperature several degrees
 above that of the surrounding air. Regulation of
 their internal body temperature is an example of
 (1) diffusion (3) respiration
 (2) synthesis (4) homeostasis