(A) Protozoa and some low-level multicellular animals There are no organs responsible for excreting liquid waste. Such waste can penetrate the cell surface directly into the water outside of it. If paramecium does not contain vacuoles will cause it to lose the balance of body fluids The contractile vacuole compression rate depends on the osmotic pressure of the water in which the animal lives, i.e. the compression rate decreases. if the osmotic pressure of the water in which it resides increases But it will speed up if the osmotic pressure of water decreases.
(B) The water mixed with salt has a higher concentration than fresh water. So the water diffuses into the paramecium. Therefore, the contractile vacuole is less compressed to remove water from the cell than when in fresh water.