A woman with a straight hairline has as child with a man who is heterozygous and has a widow's peak.
What is the mother's genotype?

aa

Explanation:

A widow's peak is the dominant genotype so one must not have that trait. If it was presented then the woman would have the genotype.

A widow's peak is dominant so the man would be either AA or Aa. Since it stated that his is heterozygous (Hetero meaning two different), his genotype would be Aa (again since a widow's peak is the dominant, it only needs one dominant genotype)

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.