Why is water at the bottom of a temperate lake likely to be close to 4°C year-round?

Name: Why is water at the bottom of a temperate lake likely to be close to 4°C year-round?
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Quizplus · Accepted Answer

Water is densest at 4°C, meaning that as water approaches that temperature, it sinks to the bottom of the lake. This creates a layer of denser, colder water at the bottom of the lake which does not mix with the warmer, less dense water at the top. As a result, the bottom water remains close to 4°C year-round.

Why Is Water at the Bottom of a Temperate Lake