Which statement best describes a fundamental difference between proteins and other macromolecules? A. Proteins are hydrophobic, so they are able to cross the plasma membrane without the use of ATP by the cell. B. Proteins contain the instructions needed for the assembly of DNA, RNA, and other organic molecules. C. Proteins are made from amino acids that vary in hydrophobicity, resulting in diverse structures and functions. D. Proteins tend to be very long polymers, so they provide more energy per gram than carbohydrates or lipids.