Which type of bone provides much of the skeleton's support and protection and is found primarily in the shaft?

• A. Cancellous bone
• B. Cartilage
• C. Compact bone
• D. Medullary cavity

Answer: (C)

Compact bone is the dense, outer layer that provides most of the skeleton’s support and protection, especially in the shaft (diaphysis) of long bones. Its compact, tightly packed structure—organized into osteons with concentric lamellae around a central canal—gives it the rigidity to bear weight and resist bending and twisting. In contrast, cancellous bone is the lighter, spongy bone found mainly at the ends of bones, where a network of trabeculae supports marrow storage and metabolic needs. Cartilage is a different connective tissue that cushions joints and supports growth regions, not a mineralized load-bearing bone. The medullary cavity is the hollow center of the shaft that houses marrow, not a bone tissue itself.