This is made up of many bones and protects the brain (skull).

• A. Pivot joint
• B. Mandible
• C. Cranium
• D. Fixed joint

Answer: (C)

This question tests identifying the structure that forms the protective shell around the brain and is built from multiple bones. The cranium fits because it is composed of several bones (and, in adults, these bones fuse at sutures) that create a rigid, protective case encasing the brain. The other options don’t match this idea: a pivot joint is a type of joint that allows rotation, not a protective skull structure; the mandible is the lower jawbone, not the shell around the brain; a fixed joint describes immovable joints in general, whereas the question focuses on the brain-protecting structure made of many bones, which is the cranium.