Which of the following are key functions of protein?

• A. Providing primary energy for daily activities
• B. Storing genetic information
• C. Regulating blood sugar alone
• D. Contributing to tissue formation and building strong muscles and a healthy immune system

Answer: (D)

Proteins primarily support growth, repair, and immune defense. They provide the building blocks for tissues, helping with growth and repairing wear and tear, especially in muscles and connective tissue. They also form antibodies and other components of the immune system, helping defend the body against infections. That’s why describing proteins as contributing to tissue formation, building strong muscles, and a healthy immune system best captures their essential roles. The other statements mix in roles that belong to other nutrients or describe only a part of protein function—energy for daily activity is mainly from carbohydrates and fats, storing genetic information is the job of nucleic acids like DNA and RNA, and blood sugar regulation is a broader process not driven by proteins alone.