Explain how the body prevents particles in inspired air from reaching the gas
exchange surfaces.

Your respiratory system prevents harmful substances from entering the lungs by using: .Mucus produced in the trachea and bronchial tubes to keep air passages moist and aid in intercepting dust, bacteria and other substances; The sweeping motion of cilia (small hairs in the trachea) to keep air passages clean

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