Answer:
Calcium
Explanation:
Parathyroid hormone (PTH) is a hormone that is secreted by the parathyroid gland. It is the major regulator of the plasma concentration of calcium ions. It regulates calcium ions in the kidney, intestine and bones.
In the kidney, is involved in the re-absorption of calcium in distal ducts and the renal collecting duct, it is also involved in activating the conversion of 25-hydroxy vitamin D into 1,25-dihydroxy vitamin D (calcitriol).
In the intestine, PTH is involved in the absorption of calcium, by increasing vitamin D production.
In the bone, it helps in regulating calcium levels; when serum calcium level is low, PTH stimulates the activity of the osteoclast, to produce more calcium.
Answer:
Many animals and plants regenerate tissues or even whole organs after injury. Typically, specialized cells at the wound site revert to a 'pluripotent' state–via a process called dedifferentiation—which means they regain the ability to develop into the various cell types required for regeneration.
Explanation:
Hope this helps
I'm not entirely sure, but I think it is B) the pulley.
The answer is nitrogen-fixing bacteria.
<span>Plants
are not able to directly use atmospheric nitrogen. It must be converted into different
form through a nitrogen cycle. In the process of nitrogen
fixation, nitrogen fixing bacteria converts atmospheric nitrogen into
ammonium. In the process of assimilation, plants incorporate
ammonium into proteins.</span>
Some legumes have a symbiotic relationship with bacteria that
live in their root system. These bacteria are called Rhizobia and have
the ability of nitrogen-fixation.
