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Tuesday, October 11, 2011

Humans Need Air

1. Air is another basic need of humans.

2. Humans need air to breathe during respiration.

3. During the process of respiration, we breathe in oxygen and breathe out
carbon  dioxide.

4. We need oxygen to produce energy in our body.

More to Learn
20% of the air is made up of  oxygen. Inhale means breathing in. Exhale means breathing out.



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