Which of the following substances is NOT typically perceived as an antigen:

Antibodies are also referred to as immunoglobulins.

Contaminated mucus is removed from the lower respiratory passageways, such as the trachea, by:

The parietal pleura is superficial to the visceral pleura.

Antibodies are also referred to as immunoglobulins.

B cells develop immunocompetence in the:

Gas exchange occurs in the:

Which one of the following structures is NOT part of the respiratory zone:

B cells develop immunocompetence in the:

The serous membrane covering the surface of the lungs is called the: