In the African countries where HIV/AIDS is a big problem the economies have big problems. People that have it are usually young people, they lack the physical power and the concentration to be effective workers, or they can not work at all, and this affects the economy because the efficiency is very low or non existent from the people that have HIV/AIDS. Also, this means that this people need medical care, an expensive one, and they usually do not have the resources to pay for it, so the governments spend big amounts of money on this as well.
To add, absolute water depth has nothing to do with the difference between shallow and deep-water waves. On the other hand, the ratio of the water’s deep to the wavelength of the wave is that one that determines it. A deep-water wave’s water molecules proceed in a circular orbit while the orbit of the molecules of shallow-water waves molecules’ orbit are elliptical.
As the earth's history was formed by a collision that led to the formation of the moon that took place about some 4 billion years ago and the earth was a then a blob of molten rock with just a thin solid film on its outer surface.
<u>What can be inferred about the different density of the earth is the earth atmospheric at that time was warm and solar radiation with a relative density and the oceanic crust has relatively more dense matter settled down and in the process known as the planetary differentiation.</u>
