Question

The substance that a wave moves through is called a __________.
a. fluid
c. track
b. medium
d. vibration

Answer 1

b. medium

The substance that a wave moves through is called aMEDIUM

NOT:
a. fluid
c. track
d. vibration

Answer 2

The substance that a wave moves through is called a B. medium.

Air is a medium. In space there is no air, and therefore, there is no medium for sound waves to travel.