Proteins have numerous important functions. For example, they are important for cell growth, repair, and maintenance. They also help maintain acid-base balance by acting as buffers. Choose the statements that correctly describe a function of proteins in the body. A. Proteins play an important role in immunity. B. Proteins help speed up chemical reactions. C. Proteins help transport nutrients and other substances. D. Proteins are stored in adipose tissue to be used as an energy source later. E. Proteins help maintain fluid balance.