What is the composition of air

Explanation:

78 percent nitrogen, 21 percent oxygen, 0.9 percent argon, and 0.1 percent other gases.

Air is mixture of nitrogen, oxygen, carbon dioxide, water vapour and a few other gases.

Explanation:

hope this helps you!!

its first and third is your answer i did the qustion the fourth isnt right

they it depends on if one believes about radioactivity, they make a geiger counter beep but maybe it was going to beep anyway electronics do wierd things all the time or it was programmed to beep near certain metals.