Answer the following question: Fact 1: Mammals generate heat mainly by keeping their metabolic rate high. Fact 2: Birds have a high metabolic rate and a high energy requirement. Given the two facts above, what mammals have a high energy requirement and generate heat?

Options are:
I. cats
II. bats
III. Crustaceans
IV. bears
V. frogs
VI. lizards
VII. birds
VIII. mammals
Answer:
VII.