Answer: The contractile vacuole will shrink, expelling more water, thereby causing the cell to shrivel.
Step-by-step explanation:
The main function of the contractile vacuole is to regulate the amount of water in the cell and to expel waste products. When a freshwater amoeba is placed in seawater which is hypertonic, the contractile vacuole will release more water in response to the concentration gradient thereby making the cell to shrivel up.