Low dissolved oxygen concentrations that occur in many bodies of water when nutrients stimulate the growth of algae that subsequently die and are decomposed by oxygen-using bacteria.
I would pick IRRIGATED. Hope that helped !
A perceptual region is one created in the mind of the viewer according to associated feelings and ideas.<span> It is a highly subjective way of looking at a geographic region .</span>
That would be the focus. The focus is indeed the point inside the earth where an earthquake takes place as well as the point inside the crust where the pressure is released. The area on the Earth's surface directly above the focus is called the epicentre.
