The question is incomplete. The complete question is attached below.
Answer:
The following are the cause, consequences and solution of the question:
Cause:
The cause may be defined as the reason due to which the situation arises. The factors that are responsible for the dead zones are the nutrient runoff from the agriculture and industrial waste that causes the algal bloom.
Consequence:
The consequences are the result of the harmful situations. The consequences of dead zone are aquatic organisms death, shifts of the marine food web and fisheries loss.
Solutions:
Solutions are the steps that might taken to solve the problem. The solutions that might taken to solve the dead zone problem are the reduction in the use of fertilizers, wetland constructions and development of the different polices.