Fact 1: Animals require water for survival. Fact 2: Water fills the oceans of the world up to sea-level making it a liquid, a type of fluid. Given the two facts above, what requires a type of fluid to survive?

Options are:
(1). snail.
(2). wind.
(3). tapeworms.
(4). mussels.
(5). stones.
(6). animals.
(7). sand.
(8). Nematoda.
Answer:
(6).