Answer the following question: Fact 1: All animals are heterotrophs. Fact 2: Proteins are an essential nutrient for heterotrophs . Given the two facts above, protein is an essential nutrient for what?

Possible answers: (1). Animals (2). Algae (3). Carbohydrates (4). health (5). recovery (6). athletes (7). humans (8). Plants
Answer:
(1).