Answer:
Hypolimnion zone
Explanation:
The ecosystem of lake consists of four following zones :
1. Pelagic zone or limnetic zone .
2. Benthic zone .
3. Littoral zone .
4. Euphotic zone .
The ecosystem of the lake includes living organisms such as the animals , plants , micro organisms etc.
Epilimnion is the top layer of a thermally stratified lake .
And the Euphotic zone lies almost in the Epilimnion.
Hence ,
Hypolimnion zone does not belong to region in a lake ecosystem .
