True
This is true because most of the nitrogen is found in the atmosphere
When blood calcium levels drop, glands embedded in the posterior thyroid secrete parathyroid hormone, which stimulates osteoclastic activity. It is made up of parathyroid glands that lie behind the thyroid glands. The reason why it is important because it controls calcium level in the blood and within the bones. It controlled by the low calcium levels in the blood it restorative parathyroid secretion whereas the high calcium levels in the blood stop the release of parathyroid hormone.
<span>The vertebrate nerve code is found dorsally while that of the crayfish is located ventrally of its body. Additionally, the ventral nerve cord of the crayfish is a solid ventral tube while that of the vertebrate is a hollow tube. All vertebrates are chordates, the dorsal nerve cord develops into nervous tissue of the brain and spinal cord; unlike the notochord which is the scaffolding for development of the bone and cartilage of the vertebral column. In the crayfish, they have a ventral nerve cord which is a collection of nerves found in the abdomen.</span>
Two populations are said to be isolated if there is no longer any Gene Flow between them.
