Which best describes what is required for any sound wave to travel?
empty space
o any medium
solid
liquid

Any medium solid, liquid or gas is required for sound waves to travel.

Explanation:

A sound wave requires a medium to travel. Sound waves are mechanical waves that is why these waves require a medium to travel. Sound waves can travel through solids, liquids, and gases.

In solids, the particles of the medium are closely packed together as compared to liquids and gases. In liquids, particles are less tightly packed and almost negligible in gases.

Therefore sound waves produce vibration in the dense or solid medium. Denser the medium faster the sound waves travel. However sound waves can not travel through empty space.

the area between the graph and the t axis

because if the tool that you are using is not balanced it there would be false mass.