Question

A visible disturbance propagates around a crowded soccer stadium when fans, section by section, jump up and then sit back down.

Answer 1

Answer:

Transverse wave formation.

Explanation:

This type of wave formation is called transverse wave formation.

Transverse wave is a wave arising when the medium's pulse is perpendicular  to the wave's path of propagation. The crowd was standing vertically, but they were arranged horizontally in the stadium, according to the question. Hence the wave form was transverse.