Which is listed as a function of proteins?

• A. Buffer
• B. Energy
• C. Antibodies
• D. Maintenance of water distribution

Answer: (C)

Proteins include antibodies, which are immune system proteins that recognize and bind specific foreign substances. This binding neutralizes pathogens or marks them for attack by other immune cells, making antibodies a distinct and essential function of proteins. While some proteins can contribute to buffering or, if amino acids are used for energy, provide energy, and some membrane proteins influence water transport, the clearly defined and specific role among the options is antibodies.