Question

where is oxygen content in a river or stream likely to be highest? a. the source b. the mouth c. the middle portion d. none of the above please select the best answer from the choices provided

Explanation:

At the source of a river or stream, water is often colder and has more contact with air - for example, from waterfalls or rapids. Cold water can hold more dissolved oxygen than warm water, and increased air - water contact promotes oxygen dissolution. As water moves downstream to the middle portion and the mouth, it may pick up organic matter that is decomposed by bacteria, which consume oxygen.

Answer:

A. the source