Which statements correctly describe the properties of air? check all that apply.

air pressure is created by the weight of the atmosphere pushing on the earths surface

denser air is heavier than less dense air

air is less dense at higher altitudes

structure is maintained and sustained by:

-cytoskeleton: gives cells coherence

-cell wall: support

-cytoplasm: shape

hope this .

you must remain stopped until the stop signal is retracted and the red lights are turned off. approaching traffic in the opposite roadway of a divided highway shall not be required to stop, even if the school bus has the stop-arm extended and the alternately flashing warning signal lamps on.