Why do Plant Cells Possess Large-Sized Vacuoles?

Answer: Vacuoles are a very important form of plant cells since they are storage units. Plants are completely incapable of any kind of movement. They cannot simply go from one place to another for food and water in case of any kind of scarcity or droughts. 

To compensate for this incapability, the plant cells have large vacuoles. These vacuoles are responsible for holding and stocking up water and other nutrients whenever available for them to be used in difficult times, helping plants in their survival. This mechanism is very helpful for plants in places with the uncertainty of water and other nutrients required by the plant.