4.10 describe the stages in the nitrogen cycle, including the roles of nitrogen fixing bacteria, decomposers, nitrifying bacteria and denitryfying bacteria (specific names of bacteria are not required)

Firstly, here's a diagram...



Okay so...

nitrogen fixing bacteria - this turns atmospheric nitrogen into nitrogen compounds (in the soil) that plants can use

decomposers - turns proteins and urea (from plants and animals) into ammonia

nitrifying bacteria - this turns ammonia into nitrates

denitrifying bacteria - this turns nitrates back into atmospheric nitrogen gas

The process repeats.

NOTE: Some of these bacterium live in the soil and some live on the root nodules of plants.