Answer:
bcz it is harmful for every living being and property
i want to say between water power or natural gases
Answer:
fastest in rivers, slowest in groundwater
Explanation:
For rivers, lakes and groundwater, self-purification is fastest in rivers and slowest in groundwater.
When groundwater becomes contaminated, it tends to remain contaminated because the dissolved oxygen levels are low or non-existent.
The answer is B. Decreases
