Answer:
Explanation:what do you mean?
A unique feature of the nucleus is that it disassembles and re-forms each time mostcells divide. At the beginning of mitosis, the chromosomes condense, the nucleolus disappears, and the nuclear envelope breaks down, resulting in the release of most of the contents of the nucleus into the cytoplasm.
Hope that helped
Scientists who do this are doing what is considered to be and called cloning. Cloning is exactly this - taking cells from one organism and trying to produce and recreate an identical (from a genetic perspective) organism.
This can be done in a routinely fashion but there are serious ethical considerations nowadays.
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.
