a. In your own words, define what a longitudinal wave is. b. Give an example of a wave that, from your own experience, you know is a longitudinal wave. What observations or evidence tells you this is a longitudinal wave?

The explanation here is:

The particles of the medium for a longitudinal wave oscillate in a parallel direction to the direction of the disturbance passing through the medium. In this case, a longitudinal mechanical wave can be created in a slinky by compressing and then releasing a number of coils at one end. The individual coils oscillate in the direction parallel to the length of the slinky and the disturbance moves along the slinky's length.