True, our ecosystem is not independent. Everything depends on everything else to survive. :)
Yes. Gymnosperms is less dense.
Answer:
<em>The four parathyroid glands make more or less parathyroid hormone (PTH) in response to the level of calcium in the blood. When the calcium in our blood goes too low, the parathyroid glands make more PTH. Increased PTH causes the body to put more calcium into the blood.</em>
<em>MARK AS BRAINLIEST!</em>
