Answer:
<em>IAU- International Astronomical Union</em>
Explanation:
The International Astronomical Union (IAU) is an organization consisting of professional astronomers from around the whole world. The astronomers in the International Astronomical Union (IAU) work together to assign names and probable functions of different celestial bodies being discovered. The aim of the International Astronomical Union (IAU) is to protect and to safeguard field of astronomy and make progress in this field.
Answer - A. Deep because there is less O2 exchange
Reasoning - Bacteria has been known to only use half a percentage which is .5 percent of O2.
There are two atoms that make up a single element