Suppose You Are Outside Wearing a Winter Coat in Very

Suppose you are outside wearing a winter coat in very cold temperature, and the coat keeps you quite warm. Which of the following describes the reason that you keep warm?

A) The coat generates a temperature gradient between your body and the surrounding air.
B) The coat is the source of the heat that keeps you warm.
C) The coat absorbs heat from the sun.
D) The coat has insulating properties that keeps you warm.