If a paramecium caudatum swims from a hypotonic to isotonic environment, will it's contractile vacuole become more active or less? Why?

The correct option is less.

Explanation:

outside an organism's body.

A hypotonic environment can be described as an environment in which the amount of solvent is more outside the cell as compared to the inside of the cell. The amount of solutes is more inside the cell. Hence, water tends to move inwards by osmosis in such an environment.

An isotonic environment can be described as an environment where the concentration of solutes and solvents is the same inside and outside of a cell.

When paramecium caudatum would be in a hypotonic environment, its contractile vacuole will be more active to pump the excess water. In an isotonic environment, there will be no or very less water for the paramecium to pump out of the body. Hence, contractile vacuole will be less active.