Pus is made of dead neutrophils, macrophages, and other tissue debris from a damaged tissue.

A. Anti-B antibodies in the donor will agglutinate RBCs of the recipient:Type AB blood does not have anti-A or anti-B antibodies in the plasma. Therefore, the donor’s plasma will not cause agglutination in the recipient.

B. Anti-A antibodies in the donor will agglutinate RBCs of the recipient:Similarly, type AB blood lacks anti-A antibodies, so this is not the cause of incompatibility.

C. Anti-A antibodies in the recipient will agglutinate RBCs of the donor:Type A, Rh-positive recipients produce anti-B antibodies. Anti-A antibodies are not involved in reacting to type AB donor cells, so this is incorrect.

D. Anti-D antibodies in the donor will agglutinate RBCs of the recipient:Rh-negative donors do not have anti-D antibodies in their plasma because they have not been sensitized. Therefore, anti-D from the donor is not the problem.

E. Anti-B antibodies in the recipient will agglutinate RBCs of the donor:Type A, Rh-positive recipients naturally have anti-B antibodies in their plasma. When they receive type AB blood, the donor RBCs carry B antigens, which react with the recipient’s anti-B antibodies, causing agglutination and making the transfusion incompatible.

A. Hilum:The hilum is the region where bronchi, blood vessels, and nerves enter and exit the lung. While important for lung structure, it is not the area that accommodates the heart.

B. Oblique fissure:The oblique fissure separates the lobes of the lung but does not form an indentation for the heart. Its role is purely in dividing the lung into anatomical sections.

C. Base:The base of the lung rests on the diaphragm and supports the lung in the thoracic cavity. It is not shaped to accommodate the heart.

D. Cardiac notch:The cardiac notch is a concave space on the medial aspect of the left lung specifically molded to fit the heart. This indentation allows the heart to sit comfortably in the thoracic cavity without compressing the lung tissue.

E. Apex:The apex is the superior tip of the lung extending above the clavicle. It is distant from the heart and unrelated to the heart’s position in the thoracic cavity.