Which part of the axial skeleton is responsible for protecting the brain?

Correct Answer: C

Rationale: The skull, part of the axial skeleton, forms a bony encasement around the brain, protecting it from injury. The vertebral column protects the spinal cord, the rib cage shields thoracic organs, and the pelvic girdle is appendicular, making 'Skull' the correct answer.

Correct Answer: A

Rationale: Bones require protection and nutrition to stay healthy. Wearing a helmet (Choice A) prevents skull fractures during activities like biking. Other correct options from the document include wearing pads, using sports equipment, avoiding trampolines, eating calcium-rich foods, and being active. Sitting all day, eating candy, and skipping exercise weaken bones, making 'wear a helmet' a representative correct choice.

Correct Answer: D

Rationale: Bones are classified by shape: long (e.g., femur), short (e.g., carpals), flat (e.g., scapula), irregular (e.g., vertebrae), and sometimes sesamoid (round, e.g., patella). 'Square,' 'cubed,' and 'triangular' are not standard categories; 'round' aligns with sesamoid bones, making 'long, short, flat, irregular and round' the most accurate.

Correct Answer: C

Rationale: The diaphysis, or shaft, of a long bone is primarily compact bone, providing strength and support. Spongy bone is in the epiphyses, hyaline cartilage covers joint surfaces, and fibrous tissue forms membranes like the periosteum, making 'compact bone' the correct answer.

Correct Answer: B

Rationale: Spongy bone consists of a network of trabeculae, bony plates that provide lightweight strength and house red marrow. Lamellae are in compact bone, lacunae contain osteocytes, and canaliculi connect them, making 'trabeculae' the correct answer.