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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Answer:
OMG Thank youuu! You are so amazing!
Explanation:
If the cell membrane did not allow nutrients to pass through, the nucleus would be unable to send out instructions. Additionally, the mitochondria is the powerhouse of the cell.
Physical barriers
immune system
body temp
