Why do animals and humans need proteins in their diet? 1. They need these proteins to incorporate directly into required tissues
2. They break down protein into amino acids needed for their particular protein synthesis
3. They cannot make their own protein
4. They need protein for cell energy

Which of the following is a good definition for the word adaptation? question 1 options: a trait that an organism survive and reproduce in its environment. a change in an organism's environment. the way in which animals obtain food. a temperature change that can cause the extinction of plants and animals.