A Polypeptide chain is a sequence of amino acids that is the foundation for the basic structure of a protein
The answer is D. Because the bird has to be noticed and the brighter the feathers the more likely the chance to be noticed.
A lipid molecule primarily is used as a storage mechanism for the cell as ATP doesn't last very long before degenerating.
Answer: c. Part of an ecosystem
Explanation: the fish, crustaceans, molluscs and bacteria are part of a community, but sand is not. Each of those species is part of a population.