The correct answer is A, parathyroid gland.
The parathyroid hormone is secreted by the parathyroid gland which <span>inhibits osteoblasts, stimulates osteoclasts,</span> reduces the calcium output by the kidneys and promotes absorption of the calcium by the small intestines. Calcitonin, secreted by the thyroid gland, also works to a similar effect.
Anatomical structure, possible diet, and reproduction evidence.
Insulin controls blood sugar by lowering it, glucagon tells the liver to release its stored sugar into the blood stream, increasing blood sugar.
The ecosystem will collapse and fail because every species are needed and play a role in the ecosystem.
Quickly... this is a harder one, because all of possible answers are the result of interactions over a long time. However, these change the surface of the earth the fastest
1.) Volcanoes
2.) Flooding
Over a long time
1.) Through the rock cycle... earthquakes, mountain forming, etc.
2.) Melting, or forming of ice... changes sea levels