Why do you think plant cells have bigger vacuoles than animal cells

The vacuole holds large amounts of water or food. to store water and food during a drought or winter

In animal cells, vacuoles are storage facilities for food, water, and wastes.  An animal cell will typically have aeveral small vacuoles.  In plant cells, the role of the vacuoles is slightly different, and instead of several small vacuoles, a plant cell has one large, central vacuole.  It's primary function is storage of water, but the water in the vacuoles in a plant cell also contributes to the plant's overall structure.  When the vacuoles are full, the cells are turgid, giving rigidity to the plant.  When the vacuoles are not full, the cells are flaccid, and the plant wilts.

the fossil record provides evidence of a common ancestor to many species.