AI-generated practice question — model-generated for extra practice, not a previous-year CBSE board question.
Thyroxin regulates the body's metabolic rate — it controls how efficiently cells convert food into energy and use it for growth. Even with adequate food intake, without sufficient thyroxin, nutrients cannot be properly utilised for cell growth and brain development. This leads to stunted physical growth and impaired mental development (a condition called cretinism in children).
The question tests your understanding that food alone is not enough — hormones like thyroxin are needed to regulate metabolism so that nutrients are actually used. Examiners expect two clear points: (1) thyroxin controls metabolism/energy use, and (2) its deficiency impairs both physical and mental growth despite food being available. Mentioning "cretinism" adds value but is not compulsory for full marks.