The human activity that is most affected as a result of an increase in the number of dead zones in the ocean is Fishing.
How is fishing affected by dead zones?
Dead zones are areas in the ocean that suffer a lack of oxygen and other resources as a result of eutrophication.
As a result, fish cannot survive in these areas which means that people cannot fish in these areas.
In conclusion, fishing is most affected.
Find out more on eutrophication at https://brainly.com/question/8499582.
