What important function do stream pools serve?
a. stream pools serve as a habitat for juvenile fish.
b. stream pools serve as a habitat for organisms that have difficulty in feeding or navigating swifter areas of the stream.
c. they have greater depth and lower velocity than other parts of the stream, thus allowing a habitat for organisms during dryer seasons.
d. all of the above

alternative D.

Explanation: Stream pools are parts of a river that are deeper and are not as fast in current as the rest of the river. Those areas are perfect for juvenile fish, which face difficulties in dealing with faster water flows due to their reduced size and strenght and also to organisms that aren't able to live in such conditions as a higher velocity when related to feeding and navigating. When dryer seasons come, the deeper areas are the less likely to get dry because of the volume of water in it, so they also allow many different organisms to survive.

explanation:

b,bacteria convert nitrates

into nitrogen gas.

d,plants and animals take in

and use nitrogen compounds.

e,bacteria break down waste    

products and return nitrogen  

to the soil.

a,bacteria convert atmospheric

nitrogen to ammonia.

c,bacteria convert ammonia

to nitrites and nitrates.