RAS question
Which disease is caused by the deficiency of iodine in the diet?
Correct answer: (B) Goitre.
Goitre, an enlargement of the thyroid gland, is caused by dietary iodine deficiency because iodine is required to synthesise thyroid hormones T3 and T4.
Explanation
Goitre is the iodine-deficiency disease tested here. It is an enlargement of the thyroid gland, and the mechanism is clear: iodine is essential for synthesising the thyroid hormones T3 and T4. The World Health Organization treats goitre as a measure for assessing the prevalence and severity of iodine deficiency disorders in populations, which directly supports the answer. India's National Goitre Control Programme used iodised salt to combat this deficiency, so the point is not just a memorised disease-name pair; it links nutrition, endocrine function, and a public-health intervention.
Why the other options are wrong
- (A) Anaemia does not fit because it is linked to iron deficiency, not iodine deficiency.
- (C) Scurvy is a Vitamin C deficiency disease, so it is outside the iodine-thyroid pathway asked here.
- (D) Rickets is linked to Vitamin D and calcium deficiency, not to iodine deficiency.
Concept
This tests deficiency diseases and the nutrient-hormone link in basic human physiology. It recurs in RAS because it connects school-level science with public-health nutrition programmes such as iodised salt intervention.