The osmotic expansion of a cell kept in water is chiefly regulated by (a) mitochondria (b) vacuoles (c) plastids (d) ribosomes.
Option B is correct Vacuoles are non cytoplasmic areas present inside cytoplasm and separated from latter by tonoplast. They are believed to be formed by expansion and pinching off from ER. There occurs a large central vacuole and many small vacuoles in plant cells. They play a major role in osmotic expansion of cell.
