Paramecia are unicellular protists that have contractile vacuoles to remove excess intracellular water. In an experimental investigation, paramecia were placed in salt solutions of increasing osmolarity. The rate at which the contractile vacuole contracted to pump out excess water was determined and plotted against osmolarity of the solutions, as shown in the graph. Which of the following is the correct explanation for the data?

When the salt concentration is larger and the cell is subjected to a hypertonic solution, water moves out of the cell. There would be no need for a Paramecium to pump water out in this case.

At low osmolarity, the cell is subject to a hypotonic solution, where water moves into the cell. Paramecia would likely try to pump water out of the cell in this condition.