Grant has a condition in which his immune system has attacked and destroyed his thyroid gland. This is an example of a(n)

A. Biliverdin: biliverdin is a green pigment formed during heme breakdown and does not contain iron.
B. Heme: the heme moiety of hemoglobin contains an iron atom (Fe²⁺) at its center that binds oxygen.
C. Bilirubin: bilirubin is a breakdown product of biliverdin and does not contain iron.
D. Globin: globin is the protein part of hemoglobin (amino-acid chains); iron is in the heme portion, not the globin polypeptide.

A. autoimmune disease: when the immune system targets the body’s own tissues (e.g., Hashimoto thyroiditis), it is classified as an autoimmune disease.
B. tissue rejection reaction: tissue rejection refers to immune attack against a transplanted (non-self) organ, not the person’s own tissue.
C. secondary immune response: a secondary immune response refers to the heightened response on re-exposure to an antigen (memory response), not self-destruction of an organ.
D. type IV hypersensitivity: some autoimmune diseases involve cell-mediated (type IV) mechanisms, but autoimmune disease is the broader correct classification; not all autoimmune thyroid destruction is exclusively type IV.