How can your nose signal a problem?

Your nose is part of your sinus system (ew!) and it can tell you if you're sick by a runny nose, congestion, and sniffles.

It can detect dangers, both inside and outside the body.

Explanation:

Outside of the body, of course, it can smell smoke and things like that, but if you're going into diabetic ketoacidosis, you'll smell a very sweet, fruity smell before you start to have seizures and other effects.

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.