The answer seems like water. We're made up of 70% of water & many of the chemical reactions necessary for live need water as a reactant or a solvent.
Hope that helps!
Explanation:
Environmental Scientists can use GPS tagging, aerial monitoring (from a plane), RFID tags (radio frequency identification device), and/or hidden cameras to track and monitor polar bears.
Chloroplasts, the cell<span> wall, and vacuoles
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