Twelve Pairs of Male Identical Twins Were Fed 1,000 Calories

Twelve pairs of male identical twins were fed 1,000 calories above the amount needed to maintain initial weight. Also, during the experiment, the twins were not allowed to exercise. The results? All men gained weight. But even more interesting was this:

A) Each twin in a twin pair gained different amounts of weight.
B) The twins gained weight in different areas of the body: For some, it was the abdomen, and for others it was the rear end.
C) The twins gained weight in the same areas of the body.
D) There was actually a negative correlation between the amount of weight one twin in a pair gained and the amount the other twin in the pair gained.