Answer:
circulatory system
Explanation:
carries oxygen, water, and nutrients to cells throughout your body. Wastes from the cells are eliminated by your respiratory system, your excretory system, and your skin. Your nervous system controls all these activities with electrical impulses.
Answer:
Many organisms found on reefs produce chemical compounds that have been used in treatments for cardiovascular diseases, ulcers, leukemia, lymphoma, and skin cancer, and many more remain undiscovered.
Explanation:
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As the population of the hares increase, the coyote population increases as they have more food to eat.
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.