题目选项分析

Laboratory rats and mice live up to 40 percent longer than usual when fed a diet that has at least 30 percent fewer of the calories than they would normally eat, but otherwise it contains all necessary vitamins and nutrients.

Laboratory rats and mice live up to 40 percent longer than usual when fed a diet that has at least 30 percent fewer calories than they would normally eat but that otherwise contains all necessary vitamins and nutrients.