D oxygen there was no free oxygen on the earth
The sun. Greenhouse gases absorb heat better. So the more of these gases, the hotter it gets. However, the earth itself is naturally heating, but it goes too fast for live to adjust to the temperatures.
Answer:
Both of these are correct
moves constantly between Earth's surface and the atmosphere
and it is matter that is essential for life
The human respiratory system<span> is a series of organs </span>responsible<span> for taking in oxygen and expelling carbon dioxide. The primary organs of the </span>respiratory system<span> are lungs, which carry out this exchange of gases as we breathe.</span>
