Question

What term refers to the coldest and densest zone, deep below the surface of a lake?

Answer 1

The hypolimnion is the term you are looking for, this refers to the deepest and coldest zone in a lake, the upper and warmer zone is called the epilimnion. 

Hope this helps you, Cheers!

Answer 2

Answer :Hypolimnion is the deep below the surface of a lake.

Explanation : Lake is in three layers

1. Epilimnion : the top of the lake

2. Metalimnion : the middle layer of the lake

3. Hypolimnion : the bottom layer of the lake

Hypolimnion term refers to the coldest and densest zone.