Blood cell formation (haemopoiesis) occurs in which of the following structures?

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: D

Rationale: Blood cell formation (haemopoiesis) occurs in red marrow, active in flat bones and long bone ends. Blood, endosteum, and canals don’t produce cells. Answer is D, per the document.

Correct Answer: B

Rationale: The occipital bone forms the cranium’s base, not a carpal, vertebra, or facial bone. Answer is B, per the document.

Correct Answer: D

Rationale: The skull houses and protects sense organs (e.g., eyes in orbits, ears in temporal bones) alongside the brain. Lungs and diaphragm are thoracic, cells are everywhere—not skull-protected—making 'the sense organs' correct.

Correct Answer: D

Rationale: Muscles consist of fibres (elongated cells) bundled together, enabling contraction. Silica is in trace amounts, polyester is synthetic, calcium/phosphorus are bone minerals, making 'groups of cells called fibres' correct.