Statement: Cases of vitamin D deficiency have risen in urban schoolchildren. Which is the most likely cause?
- A. An increase in indoor screen time and reduced outdoor play
- B. An increase in the number of schools in the city
- C. A fall in the price of milk
- D. An increase in the school year length
Explanation
Vitamin D is synthesised in skin exposed to sunlight, so less time outdoors is a direct and plausible mechanism for the deficiency. Cause and effect items are answered by asking which option supplies a mechanism, not merely which one happened at the same time. Cheaper milk would, if anything, improve intake rather than reduce it.