Final answer:
Hyperthyroidism, also known as Grave's disease, is a condition in which the thyroid gland is overactive. It is characterized by symptoms such as rapid heartbeat, heat intolerance, weight loss, goiter, and exophthalmia.
Step-by-step explanation:
Hyperthyroidism is a condition in which the thyroid gland is overactive. It is commonly known as Grave's disease, which is the most common cause of hyperthyroidism in the United States. Symptoms of hyperthyroidism include rapid and irregular heartbeat, heat intolerance, weight loss, goiter (swollen thyroid gland), and exophthalmia (bulging eyes).