Plant cell has its cell wall so that if the cell gain or lose too much water,the cell wall will maintain the shape of the cell to prevent cell from break.Plant cell also has chlorophyll so that photosynthesis can be carried out.Common cell is small for the maximum amount of diffusion rate can be carried out.Root hair cell has an extension of cell wall,so maximum of water can be taken from outside environment.
I can only give you an general idea,you will have to extend it yourself.Hope that can help you,where are you studying?Canada or New Zealand?