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.
Hyperparathyroidism is defined as an elevated total or ionized calcium level in the blood in combination with an elevation of the parathyroid hormone (PTH) level. Parathyroid hormone is secreted from the four parathyroid glands located immediately adjacent to the thyroid in the central area of the neck.