Question

How does the contractile vacuole in a single-celled organism function to maintain homeostasis?

Answer 1

Answer: "Option B- It pumps water out of the cell".

Explanation:

Vacuoles in the cell organism are responsible to maintain the amount of water in the cell body, to get stable in the environment vacuoles either  remove or absorb the water through the mechanism of osmosis or osmoregulation.

Homeostasis is the phenomenon of maintaining balance of physical and chemical conditions of organism according to the environmental conditions to survive in it.

In single celled organisms, contractile vacuole pumps out the water from the cell through osmoregulation and excess of water is pumped out by the contractile vacuole.      

Answer 2

It's b. When placed in a freshwater environment, the organism is in a hypotonic solution, so water would flow into the organism. To prevent from bursting the vacuole constantly pumps water out to make up for this.