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.
1 The Definition of Parathyroid The definition of the parathyroid is a set of glands located in the neck on each side of the esophagus. 2  The function of these glands is to regulate the amount of calcium in tâ¦.