At Altitudes Above 10,000 Feet the Thinner Air and Reduced

Multiple Choice

At altitudes above 10,000 feet the thinner air and reduced concentration of atmospheric gases begin to have an effect on many individuals,who may feel light-headed or nauseated because

A) the low pressure of the inhaled air is insufficient to fully expand the lungs.
B) the amount of hemoglobin in the blood naturally declines at higher altitude.
C) hemoglobin becomes denatured at higher altitudes and cannot effectively bind to oxygen.
D) the diffusion gradient between the atmosphere and blood plasma is so low the blood is unable to become fully oxygenated.