Saturated fatty acids lack double bonds between the individual carbon atoms, while in unsaturated fatty acids there is at least one double bond in the fatty acid chain. Saturated fats tend to be solid at room temperature and from animal sources, while unsaturated fats are usually liquid and from plant sources :)
D, The cell take in water and food some of the food dissolve to create other things for the cells and they have structures that perform to help us survive.
