Concept:Atmospheric pressure is caused by the weight of the air column above a surface, so pressure falls when less air is present overhead.
Explanation:As altitude increases, the height of the air column above a point decreases.
This means the quantity of air, and therefore the number of air molecules, pressing down from above becomes smaller.
The density of air also decreases with altitude because air molecules are spread farther apart.
With fewer air molecules, the interaction and collision among molecules and surfaces decrease.
This leads to a smaller force per unit area, which is why atmospheric pressure decreases.
Option A is incorrect because acceleration due to gravity actually decreases slightly with altitude, not increases.
Option B is incorrect because temperature generally decreases with altitude in the troposphere.
Option C is incorrect because internal energy is not the cause of atmospheric pressure.
Option D correctly states that decreased interaction among air molecules is due to the smaller quantity of air.
Answer:D. Interaction among air molecules decreases due to less quantity of air.