1) If more data on dead zones in the southern hemisphere is collected, how do you think the distribution of dead zones in this area will change?

2) The scientist that constructed this map write, "The key to reducing dead zones will be to keep fertilizers on land and out of the sea." How do you think this can be achieved?

the right option is; decreased genetic variation  

decreased genetic variation describes the effect of this environmental change.

genetic variation is the naturally occurring genetic diversities or differences between organisms of the same species in a population. genetic variation allows the survival and adaptability of a species when they encounter changing environmental conditions. when an endangered species reduces, it loses genetic variation which may not be restored even if the species rebound and will only be recovered through the gradual collection of mutations over many years.