Earth formed around 4.54 billion years ago by accretion from the solar nebula. Volcanic outgassing probably created the primordial atmosphere and then the ocean; but the atmosphere contained almost no oxygen and so would have been toxic to most modern life including humans.
Euthyroid is the state of having normal thyroid gland function. Examples of a nonfunctioning thyroid gland may be hypothyroidism, hyperthyroidism, or thyroiditis.
condition resulting in spasms of the nerves and muscles that result from low amounts of calcium in the blood caused by a deficiency of the parathyroid hormone: thyrotoxicosis: a condition caused by excessive thyroid hormones: adenectomy: excision of a gland: adrenalectomy: excision of an adrenal gland: parathyroidectomy: excision of a parathyroid gland