Higher temperature
Sunlight
Satisfying oxygen demand
None of the above
Answer is Wrong!
Answer is Right!
The correct answer is A. Higher temperature.
A higher temperature can retard the self purification of a stream because it increases the rate of chemical reactions, including those that break down organic matter. This can lead to a decrease in dissolved oxygen levels, which can harm aquatic life.
Sunlight is necessary for photosynthesis, which produces oxygen. Therefore, sunlight can help to improve the
self purification of a stream.Satisfying oxygen demand means that there is enough oxygen in the
water to support aquatic life. This can help to improve the self purification of a stream by preventing the death of aquatic life, which can release harmful pollutants into the water.Therefore, the correct answer is A. Higher temperature.