What are the steps for getting a vaccine approved in the United States?

There are 6 steps to getting a vaccine approved.

Explanation:

b is the best answer for this question.

when the displaced particles are perpendicular to the direction the wave travels, is called a transverse wave, whereas in longitudinal wave the displace practices are parallel to the direction of the wave.

in the given image:

first image shows - longitudinal wave

second image shows - transverse wave

third image shows - longitudinal wave

fourth image shows - longitudinal wave