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.
euâ¢tecâ¢tic. 1. of greatest fusibility: said of an alloy or mixture whose melting point is lower than that of any other alloy or mixture of the same ingredients. 2. of or pertaining to such a mixture or its properties: eutectic salts. 3. a eutectic substance.