Answers

2014-06-21T23:41:00+08:00
Gas exchange takes place when you inhale and exhale
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when we inhale we breathe in oxygen,when we exhale we take out carbon dioxide/gas exchange.
2014-06-22T08:00:28+08:00
Oxygen takes place when you inhaleand carbon dioxide takes out when you exhale.

hope it helps

-ninah     :)
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