Answer:
20.9 percent
Around 78% of the air is nitrogen gas, and only 20.9% is oxygen.
Explanation:
20.9 percent
Around 78% of the air is nitrogen gas, and only 20.9% is oxygen.
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The answer would be that, it can mean excessive medical tests. Hope this helps.
Using tobacco is a bad habit that a lot of people have and they need to break those habits and get rid of them
If they can learn more about how the human body ages,why some people live longer than others then perhaps they could apply these different facts in order to eventually discover our lifespan.