What would happen to red blood cells in a hypotonic solution?AThey would shrink due to osmotic water loss.BThey would rupture due to the influx of water.CThey would retain their shape due to the cell wall.DThey would swell but avoid rupturing due to the cell wall.EThey would pump out excess water with the contractile vacuole.

A blood cell placed in hypotonic solution would gain water as water will enter cell from surrounding hypotonic medium by the process of osmosis causing the cell to swell up. If the cell was placed in hypertonic solution, water would have moved out of the cell causing it to shrink. Red blood cells do not have the cell wall and contractile vacuoles and hence, would not be able to maintain their shape leading to their rupture. Thus, the correct answer is B.