Fact 1: An animal requires warmth for survival. Fact 2: Animals act through their instincts for survival. Given the two facts above, what is one instinct that animals use to stay alive?

Available choices:
(1). motility;
(2). Warmth;
(3). stability;
(4). Cold;
(5). Territory;
(6). toughness;
(7). Peace;
(8). hormones;
The answer is:
(2).