A/ Write down the genotypes of a homozygous smooth plant and a homozygous indented plant.
b A pure-breeding (homozygous) smooth plant was crossed with a homozygous indented plant.

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'd say that the moon rock is about 2.2 billion years old.