A space rover weighs less on Mars than it does on Earth. Which statement explains this difference?
A. The rover is farther from Earth.
B. The gravitational constant is smaller on Mars than on Earth.
C. The mass of Mars is less than the mass of Earth.
O D. The rover has less mass on Mars.

Assume that a person skiing high in the mountains at an altitude of h = 15100 ft takes in the same volume of air with each breath as she does while walking at sea level. determine the ratio of the mass of oxygen inhaled for each breath at this high altitude compared to that at sea level. assume that the air composition (i.e. % of air that is oxygen) is the same at sea level as it is at 15100 ft.