8. Marine animals live in salt water, which is a hypertonic environment, there is more salt in the water than in the cells. To prevent losing too much water from their bodies, these animals’ intake large quantities of salt water and then secrete the excess salt. Why is the balance of water molecules inside and outside the cell is extremely important for the survival of all organisms, including humans? here is more salt in the water than in the cells. To prevent losing too much water from their bodies, these animals’ intake large quantities of salt water and then secrete the excess salt. Why is the balance of water molecules inside and outside the cell is extremely important for the survival of all organisms, including humans?