Which of these is a biotic factor of an ecosystem?

a.
the temperature of water in a stream

b.
the bacteria that live in the intestine of a rabbit

c.
the amount of water vapor present in a rain forest

d.
the rocks that provide cover for a rattlesnake

All cells need water to survive. in order to maintain the necessary amounts, water can flow across the cell membrane from areas of higher concentration to areas of lower concentration. what is this flow of water called? a) active transport b) allocation c) diffusion d) osmosis