Final answer:
An unexpected and exaggerated reaction to a particular antigen is called anaphylaxis, which is different from an allergy to pollen that is classified as immediate hypersensitivity. The latter is one of the three types of hypersensitivity reactions, which also include delayed and autoimmune hypersensitivity. Molecular mimicry can be a cause of acquired autoimmunity, and immune tolerance refers to the body's ability to avoid unwarranted immune responses.
Step-by-step explanation:
An unexpected and exaggerated reaction to a particular antigen is called anaphylaxis. This is a severe, potentially life-threatening allergic reaction that can occur suddenly after exposure to an antigen. In contrast, an allergy to pollen is classified as immediate hypersensitivity, which is one type of hypersensitivity reaction. Hypersensitivities are maladaptive immune responses toward harmless foreign substances or self-antigens that occur after tissue sensitization, and include immediate, delayed, and autoimmune hypersensitivity. Therefore, the correct answer to the question is c) Anaphylaxis.
Moreover, the potential cause of acquired autoimmunity can include molecular mimicry, where the body's immune system confuses its own proteins with those of invaders due to similar structures. The three types of hypersensitivity mentioned are immediate, delayed, and autoimmunity. Immune tolerance refers to the body's ability to prevent an immune response to a substance known not to cause disease, such as food molecules.