Waves that spread out after passing through a hole in a barrier display. a) interference b) diffraction c) refraction

Diffraction

Explanation:

-Diffraction, is basically the bending of waves as they move around an obstacle or through an opening. In both, the cases diffraction occurs. So as the waves hit the obstacle they will bend slightly around it.

The other options, for a better understanding why it's option A:

-Interference occurs when two waves at one point or another in the same medium, overlap

-Refraction of waves is the change in its direction when it moves from one medium to another. The other factors that change with refraction are the wavelength.

be subject to a force andchange its motion

that tool is called an altimeter which measures your altitude which can be used to tell which atmosphere you are currently in, including the stratosphere.

hope this ! : )