Answer the following question given this paragraph: 

Below 200 meters is the aphotic zone. There are no primary producers here because there isn’t enough sunlight for photosynthesis. However, the water may be rich in nutrients because of dead organisms drifting down from above. Organisms that live here may include bacteria, sponges, sea anemones, worms, sea stars, and fish.


Q: Which zone is located below 200 meters from the surface?

 Choices:

- epipelagic

- observable zone

- mesopelagic

- aphotic zone

A:
aphotic zone
