You are asked to test the biochemical oxygen demand (BOD) of a stream in your town. After observing the BOD over a week, you cal
culate that the water has a BOD of 150 mg of oxygen, which is a relatively high level. This leads you to conclude that: ______ a. the water has a high level of oxygen.
b. the water is likely contaminated with high levels of pollution or waste.
c. the water quality is safe for most aquatic organisms.
d. the high level of oxygen demand is likely caused by natural decomposition
e. the water is safe for drinking.
