Q.What might be the effect on a person whose diet has less iron content?

Step 1. Recall iron's role in the chapter's content. Haemoglobin, the oxygen-carrying pigment packed inside red blood cells, requires iron as part of its structure, and the chapter notes that when old RBCs are broken down in the spleen, their iron is specifically recycled back to the bone marrow for reuse in making new haemoglobin - underlining how essential a steady iron supply is to keeping haemoglobin production going.

Step 2. Trace the consequence of low dietary iron. If dietary iron intake is too low, the bone marrow cannot make enough haemoglobin for the new red blood cells it produces (recall that RBCs are continuously replaced roughly every 120 days), so each new generation of red cells ends up carrying less haemoglobin than normal.

Step 3. Name the resulting condition. This shortfall produces iron-deficiency anaemia, in which the blood's overall oxygen-carrying capacity falls because there is not enough haemoglobin to bind and transport oxygen efficiently. …

Trace the causal chain from dietary iron, through haemoglobin synthesis in new RBCs, to …

• Naming only 'anaemia' without explaining the underlying mechanism (reduced haemoglobin synthesis). …