Preventing the transfer of heat from an organims 's body causes that organism to keep warm.
First, a hat serves as insulation against convective heat transfer.
Wearing hats serves as insulation to keep the body warm.
What serves as insulation to keep the body warm?

(A) exoskeleton
(B) wearing hats
(C) wearing glasses
(D) Animal fur
(E) sweating
(F) with their fur
(G) wearing jewelry
(H) wearing nail polish