1) Where do dead zones appear to be clustered? What patterns do you see in the distribution of dead zones around the world?

2) Do humans appear to have a correlation with the dead zones? If so, please describe the association.

3) What are the two most likely causes of the dead zones? (please don't use humans as a cause, list specific actions or byproducts of humans)

4) Describe how fertilizers cause hypoxia and consequently dead zones in coastal ecosystems.