True or false: The bones of your skeleton are alive.

Correct Answer: A

Rationale: Bones are living tissues, not inert structures. They contain cells like osteocytes, osteoblasts, and osteoclasts that maintain bone structure, repair damage, and regulate mineral content. Blood vessels and nerves within bones also support their living functions, such as growth and remodeling, making 'True' the correct answer.

Correct Answer: D

Rationale: A long bone includes the diaphysis (shaft), epiphysis (ends), and medullary cavity (marrow space). The perichondrium is a cartilage membrane, not part of mature long bones (which have a periosteum instead), making 'perichondrium' the correct answer for what is NOT included.

Correct Answer: B

Rationale: Hematopoiesis is the process of blood cell formation, occurring in red bone marrow. Endochondral and intramembranous ossification form bones, and remodeling reshapes them, making 'hematopoiesis' the correct answer.

Correct Answer: B

Rationale: Osteoblasts are cells that synthesize bone matrix, forming new bone tissue. Osteoprogenitor cells are precursors, osteocytes maintain bone, and osteoclasts resorb it, making 'osteoblasts' the correct answer.

Correct Answer: D

Rationale: A spiral fracture results from twisting forces, creating a ragged, helical break (e.g., in sports injuries). Compressed fractures shorten bones, comminuted fractures shatter them, and impacted fractures involve ends driven together, making 'spiral' correct.