How do scientists use ice to study ancient climates

Ice is very important for studying ancient climates. Ice can preserve the remains of organisms such as a Wholly Mammoth, possibly for hundreds of thousands of years. The details and phenotype of the mammoth such as its fur, can provide evidence of Earth's ancient climate, and where it occurred (which is somewhere that contains ice).

the correct option is option a

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.