Mason notices that his boat sinks lower into the water in a freshwater lake than in the ocean. What could explain this?

A floating boat displaces enough water to balance its weight. Salt water is denser than freshwater, so the boat needs to displace less salt water to float and sits higher in the ocean. In freshwater, it must displace more water and sinks lower. Therefore, the explanation is that salt water is more dense than freshwater.

AI-written and checked against the verified answer.