A serious allergic reaction to foreign proteins is termed:

A) anisocytosis.
B) anaphylaxis.
C) allergy.
D) anemia.

Anaphylaxis is a serious and potentially life-threatening allergic reaction to foreign proteins, such as those found in certain foods or medications. It can cause symptoms such as difficulty breathing, swelling, and a drop in blood pressure. Anisocytosis is a condition in which red blood cells are unequal in size, allergy refers to a range of immune responses to allergens, and anemia is a deficiency of red blood cells or hemoglobin in the blood.