As a New Assistant in a Weight-Loss Research Laboratory,you Are

As a new assistant in a weight-loss research laboratory,you are given a tour of the mouse laboratory.Why is the leptin-deficient mouse much larger than its leptin-sufficient counterpart?

A) Leptin deficiency causes lower levels of ghrelin
B) Leptin deficiency enhances appetite and decreases energy expenditure
C) Leptin deficiency causes psychological depression,which leads to increased food intake
D) Leptin deficiency reduces the desire to do physical activity,resulting in more excess energy available for fat storage