Biochemical oxygen demand (BOD) is a measure of the amount of oxygen consumed by microorganisms during the decomposition of organic matter.

Biochemical oxygen demand (BOD) is a measure of the amount of oxygen consumed by microorganisms during the decomposition of organic matter.

• A. Oxygen produced by photosynthesis
• B. Oxygen dissolved in water not affected by organisms
• C. Oxygen consumed by microorganisms during decomposition
• D. Oxygen released during plant respiration

Answer: (C)

Biochemical oxygen demand shows how much oxygen microorganisms require to break down organic matter in water. The key idea is oxygen consumption by microbes during decomposition, so the correct description is oxygen consumed by microorganisms as they decompose organic material. The other ideas describe oxygen production, oxygen that remains unaffected, or oxygen released during plant respiration, none of which reflect the microbial consumption at the heart of BOD. In practice, a higher BOD indicates more organic pollution and greater potential for oxygen depletion in aquatic environments.

Biochemical oxygen demand shows how much oxygen microorganisms require to break down organic matter in water. The key idea is oxygen consumption by microbes during decomposition, so the correct description is oxygen consumed by microorganisms as they decompose organic material. The other ideas describe oxygen production, oxygen that remains unaffected, or oxygen released during plant respiration, none of which reflect the microbial consumption at the heart of BOD. In practice, a higher BOD indicates more organic pollution and greater potential for oxygen depletion in aquatic environments.