Which of the following characteristics is common to Amoeba and Paramecium?

The characteristic that is common to Amoeba and Paramecium is the presence of a contractile vacuole. A contractile vacuole is a specialized organelle found in many single-celled organisms, including Amoeba and Paramecium. Its primary function is to pump excess water out of the cell, helping to maintain the proper balance of water and solutes within the cell. Both Amoeba and Paramecium live in aquatic environments where they are constantly taking in water by osmosis. If they were to accumulate too much water, they could burst, so the contractile vacuole is important for preventing this from happening. While both Amoeba and Paramecium also have other organelles, such as the oral groove and cilia (respectively), the presence of a contractile vacuole is the characteristic that they share in common.