Q: Maintaining a high metabolic rate takes a lot of what?


Read this paragraph and choose the correct option from the provided answers:

Maintaining a high metabolic rate takes a lot of energy. The energy must come from food. Therefore, mammals need a nutritious and plentiful diet. The diets of mammals are diverse. Except for leaf litter and wood, almost any kind of organic matter may be eaten by mammals.

 Choices:

- food

- calories

- fuel

- energy


A:
energy