Which statement about nonspecific (innate immunity) is true?.

The correct answer is Choice C. -

Choice A rationale:

The bicuspid valve, also known as the mitral valve, prevents backflow from the left ventricle to the left atrium. -

Choice B rationale:

The semilunar valves include the aortic and pulmonary valves, but neither prevents backflow into the right atrium. -

Choice C rationale:

The tricuspid valve prevents backflow from the right ventricle to the right atrium. -

Choice D rationale:

The aortic valve prevents backflow from the aorta to the left ventricle.

hoice A rationale:

Inspired gas passes through the convoluted air passages of the nasopharynx and pharynx which generates turbulence. This turbulence increases evaporative heat exchange between the air and the mucosa. The nasal mucosa is the lining of the nasal cavity. It moistens air that is coming into the body during inhalation.

Choice B rationale:

The sphenoid is a bone located within the skull and does not directly contribute to the heating and humidification of air.

Choice C rationale:

The nasopharynx is part of the pharynx, located above the soft palate. It serves as an air passage way connecting the nasal cavity to the throat and does not directly heat or humidify the air.

Choice D rationale:

The oropharynx is also part of the pharynx, located between the soft palate and the epiglottis. It serves as a passageway for both air and food but does not directly heat or humidify the air.