the graph above depicts the human population of the world from 1050 to 2050 (projected). with an ever increasing human population, we pose a threat to our own planet in many ways. in terms of sustainability, which of these is not vital to this population growth?
a) the air quality is deteriorating
b) our natural resources are depleting
c) birth control policies should be strictly enforced
d) the food industry can't keep up with the demand of a growing population

they deliver oxygen to the blood

well, that's easy; the answer's c, "it reduces contamination of the water and substrate of the estuary."

hypoxemia refers to a below usual concentration of oxygen in the blood, mainly in the arteries. hypoxemia is an indication of an issue associated with circulation or breathing and may lead to various symptoms like shortness of breath.  

the condition is identified by determining the level of oxygen in the blood sample obtained from an artery. it can also be predicted by determining the oxygen saturation of the blood with the application of a pulse oximeter.  

the normal arterial oxygen is about 75 to 100 mm hg. the values underneath 60 mm hg is generally considered with the requirement for supplemental oxygen. the normal pulse oximeter readings generally range between 95 to 100 percent. the values under 90 percent are regarded as low.  

in the given case, the oxygen saturation is measured at 93 percent, hence, there is no need to administer oxygen, that is, one should withhold oxygen.