At the opposite extreme(相反的极端) from a perfectly elastic collision(理想弹性碰撞) is one in which the colliding bodies(物体) stick(粘) together as would two lumps of putty(油灰块).

Which is not the major functions of fats?（ ） A: It can maintain body temperature. B: It can protect the viscera from colliding injury. C: It can maintain the structure and function of biomembranes, convert to some physiological important substances. D: It is the most concentrated source or food energy. It provides 37.6kJ of energy per gram.