Well let's see...cells have to maintain some sort of nutrition usually in the form of glucose. Cells also need to be able to dispose of wast products, so I think for 1 and 2 you could say eat and purge wastes. For the third blank, a membrane is said to be semipermeable meaning that it will let in some things and not others. For the fourth blank...diffusion occurs down a concentration gradient, and it does depend on temperature and concentration. Hope this helps!
