In mice, a true-breeding female with a normal spine is crossed to a true-breeding male with a crooked spine. All of the F1 offspring have normal spines. The F1 female offspring are then crossed to true-breeding males with a crooked spine. All of the F2 offspring have normal spines. These are observations are consistent with:

Maternal effect and maternal inheritance

Explanation:

These two organelles contain DNA and control certain traits in the offspring. Those phenotypes that are controlled by nuclear factors found in the cytoplasm of the female are said to express a maternal effect. Those phenotypes controlled by organelle genes exhibit maternal inheritance.

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.