How does the structure of bones relate to their function?

The structure of bones is intricately designed to serve various critical functions in the body, particularly support and weight-bearing capabilities. The correct choice emphasizes that bones possess a rigid structure, which is essential for providing the skeletal framework that supports body weight and maintains shape. This rigidity is primarily due to the mineral composition of bones, particularly hydroxyapatite—a crystalline structure made up of calcium and phosphate—which grants bones their strength and durability.

Additionally, while bones are indeed relatively lightweight due to their semi-hollow structure (such as the medullary cavity in long bones), this lightweight feature does not compromise their ability to effectively support and protect vital organs. The combination of strength, rigidity, and a certain degree of lightweight properties allows bones to efficiently fulfill their structural roles while also facilitating movement through the musculoskeletal system.

Understanding this relationship between bone structure and function is vital in animal physiology, as it explains how organisms can maintain mobility, stability, and protect internal organs while supporting the complex mechanics of movement.