What meiotic process, relative to the number of chromosomes of a given species, accounts for a significant amount of genetic variation in gametes?

The pachytene stage of the prophase I in the meiosis I division, the process of recombination occurs. The recombination is the process of exchange of gentic material of the same allele between the sister chromatids.

As the recombination result in the exchange of genetic material between sister chromatids, this result in the genetic variations in the progeny.

So, in meiosis 1 the recombination at the pachytene stage of prophase 1 causes a significant amount of genetic variation.

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.

i think its the first one