Multiple choice

_____ is necessary for the clotting of blood, beating of the heart, contraction of muscles and the functioning of the nervous system.

  1. Magnesium

  2. Potassium

  3. Sodium

  4. Calcium

Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Calcium ions are essential for blood clotting, muscle contraction, nerve impulse transmission, and maintaining a regular heartbeat.