You are screwed. Good luck!
The upper class consisted of the royal family, rich landowners, government officials, important priests and army officers, and doctors. The middle class was made up chiefly of merchants, manufacturers, and artisans. The lower class, the largest class by far, consisted of unskilled labourers.
How old the rock is
thats my answer
This process is known as thermohaline circulation. In the Earth's polar regions ocean water gets very cold, forming sea ice. As a consequence the surrounding seawater gets saltier, because when sea ice forms, the salt is left behind. As the seawater gets saltier, its density increases, and it starts to sink.