Downwelling  ________.

             form the base of the food chain in the ocean

The most problematic greenhouse gas produced from most landfills is          

Macronutrients _____.

Aeration tanks are used in wastewater treatment plants to reduce _____ because of the high              .

For compound C,  17 mg/kg probably represents         .

The most important organ in clearing toxicants from the body is the _____which makes them           so they can be removed from the body.

A chronic exposure is:

Industrial ecologists _________.

Coal bleaching is the loss of_______from coral that can result from               .