Fact 1: Friction causes an object to lose energy. Fact 2: Ultimately, frictional processes convert all of a wave's energy into heat. Given the two facts above, what is energy lost to?

Pick your answer from:
(1). heat.
(2). health.
(3). Bats.
(4). squids.
(5). living.
(6). life.
(7). cells.
(8). horses.
The answer is:
(1).