AP PSYCHOLOGY

Detailed explanation-1: -Most living things need oxygen to survive. Oxygen helps organisms grow, reproduce, and turn food into energy. Humans get the oxygen they need by breathing through their nose and mouth into their lungs. Oxygen gives our cells the ability to break down food in order to get the energy we need to survive.

Detailed explanation-2: -Biochemical oxygen demand (BOD, also called biological oxygen demand) is the amount of dissolved oxygen needed (i.e., demanded) by aerobic biological organisms to break down organic material present in a given water sample at certain temperature over a specific time period (Kaiser, 1998).

Detailed explanation-3: -Biological oxygen demand is important for water quality because it provides an index to assess the effect discharged wastewater will have on our environment. BOD is used extensively for treating wastewater, as decomposition of organic waste by microorganisms is commonly used for treatment.

Detailed explanation-4: -The dissolved oxygen that microorganisms like bacteria need to oxidize, and organic substances in water, are referred to as BOD. It is a metric for determining the quality of water.