It might be 23% because 77% of water covers earth and most of the water is either polluted or salt water.
sapropollenin i<span>s a polymer that tesist all kinds of environmental damages</span>
<span>The answer to this question would be: tissues; decrease
Oxygen is delivered to the tissue by the heart. It will be unloaded in the tissue, causing the oxygen level in the blood to be decreased. After that, the blood also picks up the carbon dioxide so its level will be increased.
In lungs, the carbon dioxide will be unloaded and oxygen will be loaded back into the blood.</span>
It should be Ozone, hope that helps.
Trees release CO2 which is Oxygen.
Plants release water vapor through Photosynthesis.