In most fairly large temperate-zone lakes that freeze during the winter, turnover takes place _______ a year.
A) once
B) twice
C) three times
D) four times
E) None of the above; these lakes do not turn over.

Question

Quizplus · Accepted Answer

In most fairly large temperate-zone lakes that freeze during the winter, turnover takes place twice a year. This typically occurs in the spring and fall when the surface water cools, becomes denser and sinks to the bottom, while the bottom water warms and rises to the surface. This turnover helps to distribute oxygen, nutrients, and other important substances throughout the lake, supporting the diverse aquatic ecosystem.

In Most Fairly Large Temperate-Zone Lakes That Freeze During the Winter