Answer:
While humans, as well as other vertebrates, have a closed blood circulatory system (meaning that the blood never leaves the network of arteries, veins and capillaries), some invertebrate groups have an open circulatory system containing a heart but limited blood vessels.
Explanation:
The process is the difference in atmospherical pressure where air moves from higher to lower pressure area creating winds of various speeds
Answer:
With a cold comes inflammation of the structures around the vocal cords. With the inflammation comes swelling of those structures. Thicker vocal cords vibrate more slowly and give a lower pitch.
