<span>The ventricles are the part of the heart that are responsible for the pumping action to move blood throughout the body. Therefore, the muscles in the ventricles are much larger and thicker to do their job properly. The atrium only has to pump blood through an open valve (the tricuspid valve) into the right ventricle. There is much less resistance to this flow of blood so much less muscle is needed. </span>
The cell membrane is a selectively permeable membrane which controls what goes in and out to ensure that not just anything comes in through it's own accord.
Answer:
Explanation:
1: it left rich black soil
2:The rosetta stone
3: not 100% on this one but i think it's they had planned grid-like streets
4:The began near the yellow and yangtze rivers
I did this last year. im pretty sure they are correct but am really sorry if they aren't. hope it helps