Does Mars has Oxygen? Can we breath on Mars?​

There is Oxygen in Mars comprising the 0.13% of it's atmosphere. With that, it is still impossible for humans to breathe on the said planet without suits with oxygen supply.

yes

Explanation:

Mars atmosphere is dominated by carbon dioxide (CO2) at a concentrated of 96%. Oxygen is only 0.13%.

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.