AIIMS 2014 Zoology Human Biology MCQ Question

The correct answer is B) thymus because the thymus gland plays a crucial role in the immune system, particularly in the development of T-cells, which are vital for immune responses. As individuals age, the thymus gradually shrinks and undergoes atrophy, leading to a decline in immune function, hence it is often referred to as the "clock of ageing." In contrast, the other glands listed do not have a direct correlation with the ageing process in the same manner.