Q: Fact 1: Thick fur can be used for keeping warm. Fact 2: Otters fur is the thickest fur of any animal. Given the two facts above, what can be used to make clothing for keeping warm?

pick from the following.
(1). cellulose;
(2). bamboo;
(3). heat;
(4). fibrous;
(5). otters;
(6). energy;
(7). chemicals;
(8). Loose;
A:
(5).