Which of the list below is a cell that reabsorbs bone?

Correct Answer: D

Rationale: Osteoclasts reabsorb bone, breaking it down. Osteons are structures, osteoblasts form bone, osteocytes maintain it. Answer is D, per the document (note: text error corrected—osteoblast matures to osteocyte, not osteoclast).

Correct Answer: A

Rationale: Haemopoiesis is blood cell formation in bone marrow (‘poiesis’ = making). Clotting is haemostasis, crenation is osmotic, and proportion isn’t haemopoiesis. Answer is A, per the document.

Correct Answer: A

Rationale: Osteocytes are mature bone cells in lacunae of compact bone, derived from osteoblasts. Osteons are structures, not cells. Answer is A, per the document.

Correct Answer: A

Rationale: Haemopoiesis occurs in red marrow (active), found in medullary cavities and epiphyses, not yellow marrow (inactive) or cartilage plates. Answer is A, per the document.

Correct Answer: C

Rationale: Synovial joints have a fluid-filled cavity (synovial fluid), not discs in all, and aren’t amphiarthroses or cartilaginous. Answer is C, per the document.