Clothes keep us warm in winter because they :
(1) supply heat
(2) do not radiate heat
(3) prevent air from contacting the body
(4) prevent the heat of the body from escaping
Answer: (4) It is just because woollen clothes have fibres and between those fibres air is trapped which reduces heat loss. Air reduces heat loss because it is an insulator or poor conductor of heat. Hence, all the heat from our body gets trapped inside the clothes which makes us feels warmer with the clothes.