The diagram below shows a longitudinal wave at one instant in its motion. Each oval represents a particle acted on by the ener the wave as it moves from left to right. Which line on the diagram indicates a region of rarefaction?

Answer:
the first line
Explanation:
A rarefaction is a region in a longitudinal wave where the particles are furthest apart. ... The region where the medium is compressed is known as a compression and the region where the medium is spread out is known as a rarefaction.
use this picture as a reference: