Flat bones primarily serve what function?

Flat bones are primarily known for their protective function. They are structurally designed to shield vital organs and provide a surface for muscle attachment. Examples of flat bones include the skull, ribs, and sternum, which are all vital in safeguarding the brain, heart, and lungs.

While flat bones do participate in muscle attachment, their primary role is more about protection. They also contribute to blood cell production, particularly in the bone marrow found within some flat bones, such as the sternum and pelvis, but this is not their main function. Energy storage is typically associated with adipose tissue found in long bones, rather than flat bones. Therefore, the primary function of flat bones is indeed to provide protection, making this the most accurate answer.