Please explain, no copy paste

Under Conditions at Mt Everest answer (xiv - xviii): i. How does the altitude affect the percent concentration of Oxygen? (Is this the same, less or more than under sea-level conditions?) ii. What is the pressure of Oxygen in mm Hg on Mt Everest? ii. What is atmospheric mmHg of Oxygen level on the mountain? v. How does the pressure on Mt Everest compare to the Oxygen entering the lungs? v. How does this make breathing easier or harder