What are dead zones?
a.They refer to the vast net cages in ocean inlets or freshwater lakes that are used to cultivate seafood.
b.They refer to a specific area of land that is infertile.
c.They refer to the areas that have been damaged because of heavy storms eroding the topsoil.
d.They refer to the pressure placed on water resources by human activities.
e.They are columns of oxygen-depleted ocean water in which marine life cannot survive.