Which term best matches the following definition: Condition that results from severe thyroid hormone insufficiency?

• A. Hypothyroidism
• B. Hyperthyroidism
• C. Endocarditis
• D. Leukemia

Answer: (A)

Thyroid hormone sets the pace of the body's metabolism. When production is severely low, the body's processes slow markedly, a condition called hypothyroidism. This matches the definition because it describes a condition arising from a lack of thyroid hormone. The other terms refer to different problems: hyperthyroidism is the overproduction of thyroid hormone, endocarditis is an infection of the heart lining, and leukemia is a cancer of blood-forming cells, none of which fit the idea of low thyroid hormone causing a systemic slowdown.