Answer:
There's a video called Drawing Position vs Time Graphs made by MrDGenova that may help you, it's only three minutes long.
Explanation:
Hope that helps, if not, you could tell me what you don't understand and I could try explaining it in further detail.
I believe the answer is C- payload
Air pressure is the wi get of air molecules pressing down on the earth. The pressure of the air molecules changes as you move upward from sea level into the atmosphere, the highest pressure is at sea level where the density of the air molecules is the greatest.