Your cardiovascular system is made up of the heart and blood vessels (arteries, capillaries, veins).
If the cell is green, that would mean that it contains the pigment of chlorophyll (suggesting that it is a plant cell). In addition, a rigid cell wall means the cell is part of a stronger structure, so it is likely a plant cell.
I think that the water concentration in the cell is more than the one in the solution, so the water in the cell moves to the solution and then the cell shrinks
