Haemoglobin carries oxygen in the blood and is a ______-containing compound.

Correct answer: (c) Iron

Explanation

Haemoglobin is the red pigment of red blood cells. Each molecule has four haem groups, and each haem holds an iron (Fe²⁺) atom to which an oxygen molecule binds. So each haemoglobin molecule can carry four oxygen molecules.

A shortage of iron lowers the haemoglobin level and causes anaemia. Magnesium is the central atom of chlorophyll, and copper is the metal in haemocyanin, the blue blood pigment of some molluscs and crustaceans.