relating to, involving, or requiring an absence of free oxygen.
or
relating to or denoting exercise that does not improve or is not intended to improve the efficiency of the body's cardiovascular system in absorbing and transporting oxygen.
It requires water to do so. And for the uptake of water from it's surroundings, a cell must keep it's internal fluid or the cell sap at a higher solute concentration or lower water potential. This results in "endosmosis". Once water enters the cell, the protoplast swells and the cell membrane exerts a pushing force on the cell wall which is called the turgor pressure.
So basically, it has to regulate the flow of solute particles or ions across its cell membrane and keep its cell sap at a higher solute concentration or lower water potential, compared to its surrounding medium
The oceans also regulate the global climate; they mediate temperature and drive the weather, determining rainfall, droughts, and floods. They are also the world's largest store of carbon, where an estimated 83% of the global carbon cycle is circulated
I believe it's number 4 because similar to when wrong blood types are transfused into a body, the immune system will see the donated organ as a foreign object and attack it to protect the organism (human).
