Question

which phrase describes density?
height of a point above sea level
force pushing on an area or a surface
amount of mass in a certain volume
amount of matter an object contains

Explanation:

• The height of a point above sea level is related to elevation, not density.
• Force pushing on an area or a surface is the definition of pressure.
• The amount of matter an object contains is mass.
• Density is defined as mass per unit volume, which matches "amount of mass in a certain volume".

Answer:

amount of mass in a certain volume