Give four examples of things that need to be interchanged between an organism and its environment.

What two different ways can this exchange occur in (include examples as well)

What two factors affect the amount of each material that needs to be exchanged?

What increases the efficiency of how much a substance is exchanged?

Give some examples of features of specialised exchange surfaces.

Give the equation for working out diffusion.

What is a disadvantage of a thin diffusion pathway and how do we overcome it?

What is the surface area to volume ratio like for:
1) small organisms
2) large organisms

For organisms with a large surface area to volume ratio, organisms have evolved to have the two following features which help overcome the problem: