Question

which phrase describes air pressure?
decreases with denser air
decreases as altitude decreases
equals mass divided by volume
decreases as a result of fewer air particles pushing down

Explanation:

• Denser air has more particles, increasing pressure, so first option is wrong.
• Lower altitude has more air above, so pressure increases, not decreases, making second option wrong.
• Mass divided by volume is density, not air pressure, so third option is wrong.
• Air pressure comes from air particles pushing down; fewer particles mean less downward push, so pressure decreases.

Answer:

decreases as a result of fewer air particles pushing down