In humans, calcium plays a role in

(A) Bone formation
(B) Blood clotting
(C) Muscle function
(D) Blood formation

Choose the correct answer from the options given below:

(A), (B) and (C) only

The correct answer is Option (2) → (A), (B) and (C) only

• (A) Bone formation: Correct. About 99% of the body's calcium is stored in the bones and teeth, where it provides structural rigidity and strength.

• (B) Blood clotting: Correct. Calcium ions ($C{a}^{^2+}$) are essential "clotting factors" (Factor IV). They act as a bridge that allows various proteins to bind together to form a stable blood clot after an injury.

• (C) Muscle function: Correct. Calcium is vital for muscle contraction. When a nerve signals a muscle to move, calcium is released into the muscle fibers, allowing the proteins actin and myosin to interact and pull against each other.

• (D) Blood formation: Incorrect. Blood formation (haematopoiesis) primarily requires Iron (for hemoglobin), Vitamin B12, and Folic acid.