One property that makes ddt hazardous over the long run is that ddt is
a. an insecticide.
b. a perfect pesticide.
c. subject to biological magnification.
d. deadly to herbivores.

C. subject to biological magnification.  

Explanation:

DDT is an insecticide that exhibits slow metabolism and excretion. The slow breakdown of DDT causes it to accumulate in fat tissues of organisms. Biological magnification refers to the process of increased concentration of toxic chemicals in the tissues of living beings of higher tropic levels. The accumulated higher concentration of DDT poses harmful effects on the health of top consumers.

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.  

it is called the mitotic spindle