In a plant cell, how are the functions of the cell wall and the cell membrane alike? how are they different.

All cells have cell membranes, but only some have cell walls too, for example
Animal cells only have cell membranes, which are flexible.
Plant cells have cell walls made out of cellulose and fungi have cell walls made out of chitin. 
Cell membranes help protect cells and hold them together, and take in food and water and eliminate waist. 

Ithink it has to be c. humans