Woolen clothes are warmer than cotton clothes because

Woolen clothes are warmer than cotton clothes primarily because they [D] are good insulators of heat. Wool fibers have natural properties that trap air pockets within the fabric, creating a barrier against heat loss. This insulation prevents body heat from escaping and external cold air from penetrating, effectively maintaining warmth. In contrast, cotton fibers lack the insulating properties of wool and do not trap air as effectively, making cotton clothes less suitable for retaining warmth. While woolen clothes may also be heavier than cotton clothes (option [C]), their superior insulation properties are what primarily contribute to their warmth. Options [A] and [B] are inaccurate as wool’s warmth is not due to its ability to absorb or distribute heat but rather its effectiveness as an insulator. Therefore, option [D] provides the most accurate explanation.