The disease caused to deficiency of iron in known as?

The answer is C) Anaemia. Iron is needed to make haemoglobin, the protein in red blood cells that carries oxygen. When iron intake or absorption falls, haemoglobin and red cell counts drop, and the result is iron-deficiency anaemia. This is a nutritional deficiency disease.

• Colour blindness is a genetic disorder, most often X-linked, affecting cone cells. It is not caused by lack of any nutrient.
• Night blindness is caused by deficiency of Vitamin A, which is needed to make rhodopsin in the retina.
• Tuberculosis is an infectious disease caused by the bacterium Mycobacterium tuberculosis. It is not a deficiency disease.

The core concept is the link between micronutrients and specific disorders. This matters for Mains under health and nutrition, where the government's Anaemia Mukt Bharat programme (launched in 2018) and fortification or supplementation policies are relevant. Note that NFHS-5 shows anaemia prevalence still high among women and children.

Trap: Candidates often confuse the nutrient and the disease, or assume every blindness is a Vitamin A problem. Colour blindness is genetic and has no nutritional cause.