Answer: The order is a-b-c-d-e-
Explanation:
In winter there is a thin layer of ice that covers the water of the lakes below. As spring approaches (a) surface water warms to 4 C and sinks. This eliminates the thermal stratification and (b) water mixes, bringing oxygen to the bottom and nutrients to the surface. In Summer, the lake presents again a clear thermocline profile as (c) warm surface water is separated from cooler bottom water. In the fall, (d) surface water cools to 4 C and sinks. This causes the lake water to mix once more (e) bringing oxygen to the bottom and nutrients to the surface.