Which statement about the skeletal system is true?

• A. It is the primary site of hormone production.
• B. It accounts for about 20% of body weight and provides a framework to support and protect soft organs.
• C. It stores energy primarily as fat in adipose tissue.
• D. It is composed mainly of smooth muscle tissue.

Answer: (B)

The main idea here is that bones give the body its framework and protection. The skeletal system provides rigid support for the body, anchors the muscles to create movement, and shields vital organs (like the skull protecting the brain and the rib cage protecting the heart and lungs). It also accounts for a sizable portion of body mass—roughly a fifth in many adults—which reflects the solid, mineralized matrix of bones. Beyond structure, bones store essential minerals such as calcium and phosphorus and house marrow that can produce blood cells, making the skeleton a multifunctional system.

This statement is the best fit because it captures the key structural role of the skeleton and its proportionate weight. The other options don’t fit: hormones aren’t primarily produced by bones (hormones come mainly from endocrine glands, with bone playing only a smaller, specialized endocrine role). Energy storage is primarily in adipose tissue, not bone. And bones aren’t made of smooth muscle tissue; they are mineralized connective tissue, while skeletal muscle is a separate tissue type that attaches to bones to produce movement.