Q: Mammals generate heat mainly by what?\nOptions:\n- (A) hugging mammals\n- (B) calorie counting\n- (C) with their fur\n- (D) energy of moving objects\n- (E) burning calories\n- (F) sweating\n- (G) selling fur coats\n- (H) flow of electrons
Let's think step by step below.

User
Mammals generate heat mainly by keeping their metabolic rate high. And resting metabolic rate is a big contributor to calories burning. Mammals generate heat mainly by burning calories.
Thus, the answer is (E).
Assistant