Where are the tonsils located?

A. Trachea: The trachea is the airway that leads to the lungs, but it does not contain tonsils.

B. Esophagus: The esophagus is the tube that connects the throat to the stomach, and it does not contain tonsils.

C. Pharynx: The tonsils are located in the pharynx, which is the region of the throat behind the mouth and nasal cavity. They play a role in the immune system by trapping pathogens that enter the body through the mouth and nose.

D. Larynx: The larynx is the voice box, located below the pharynx, and does not house tonsils.

A. Lysozyme within tears destroy bacteria.: Lysozyme is an enzyme found in tears that helps to break down the cell walls of bacteria, acting as a chemical barrier and part of the innate immune system's first line of defense.

B. Chemotaxis attracts phagocytes to the site where the pathogen invaded.: This is part of the inflammatory response, which occurs after the first line of defense has been breached; therefore, it is not considered a first line of defense action.

C. Natural killer cells are the first lymphocytes to react to infection.: While natural killer cells play an essential role in the immune response, they are part of the second line of defense and respond after pathogens have entered the body.

D. Phagocytes ingest microbes when they enter the body.: This is part of the second line of defense, as phagocytes respond to pathogens that have breached the first line of defense, which includes physical and chemical barriers.