Some of your dna may not code for any protein and has no known function in gene regulation; it is sometimes referred to as "junk" dna. how do nucleotide sequences of "junk dna" evolve?

They evolve through genetic drift.

Explanation: Junk DNA refers to noncoding sections of a genome. It consists of repeated segments scattered randomly throughout the genome generated through transposition or movement of sections of DNA to different positions in the genome.

Genetic drift is the change in the frequency of an allele in a population due to random sampling of organisms. This process is caused by spontaneous mutations and may cause the alleles to disappear completely and thereby reduce genetic variation. Many of these genetic alterations are in regions of "junk DNA"

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.