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

stimulus is a change in the environment that causes an organism to react. the response is the reaction to the stimulus. some examples of stimuli for zebras are drought, to many predators, and bad feeding grounds such as dead grass or plants. zebras respond to stimuli just like all other living organisms