Flat bones are thin, flat, and curved; form the ribs, breastbone, and skull.

• A. These bones are dense and heavy
• B. They store fat
• C. These bones are thin, flat, and curved. They form the ribs, breastbone, and skull.
• D. They connect muscles

Answer: (C)

Flat bones are defined by their thin, flat, curved shape, which creates broad surfaces for protection and for muscle attachment. This shape suits their main roles: protecting vital organs and providing ample area for muscles to attach. The ribs, breastbone, and bones of the skull are classic examples because they form the rib cage and cranial vault, protecting the heart, lungs, and brain while offering large surfaces for muscle attachment and leverage. The statement reflects this defining trait and the bones involved, making it the correct description. Other options describe properties that don’t capture the distinctive shape and protective/muscular-attachment roles of flat bones.