Question

Dumping sewage into rivers results to which of the following events?

• A. Increase in dissolved oxygen in the water body.
• B. Population decrease of microorganisms.
• C. Population explosion of microorganisms.
• D. Purification of the water body.

Answer 1

The correct option is

Population explosion of microorganisms.

Microorganisms in water bodies use up dissolved oxygen to break down nutrients and other organic compounds. When sewage is dumped into rivers, the organic matter in the water body increases suddenly, which causes a population explosion of microorganisms which feed on the sewage and replicate exponentially.