Rock is considered an ecosystem because based on the definition of ecosystem. A rock is happens to be in our environment which makes it part of our ecosystem. 1 person found this useful.
Parathyroid hormone. Parathyroid hormone (PTH), also called parathormone or parathyrin, is a hormone secreted by the parathyroid glands that is important in bone remodeling, which is an ongoing process in which bone tissue is alternately resorbed and rebuilt over time. It essentially increases blood calcium levels.
The thyroid gland produces two vital metabolic hormones â triiodothyronine (T3) and thyroxine (T4). T3 and T4 are produced using iodine, with T3 containing three iodine atoms and T4 containing four.