B3

Question 1

explain the difference between diffusion and osmosis

Answer 1

diffusion is the movement of particles from a high concentration to a low concentration. Whereas osmosis is the movement of water particles from a high concentration to a low within water.

Question 2

explain why active transport requires energy, whereas diffusion and osmosis do not

Answer 2

because the particles have to move from a gradient from low to high which requires energy

Question 3

describe 2 ADAPTATION of the villi which help the small intestine to function

Answer 3

1) increase surface area so more food can be absorbed

2) very good blood supply to aid absorption