Why are rivers so important in southeast asia?

In 1915 the german geologist and meteorologist alfred wegener first proposed the theory of continental drift, which states that parts of the earth's crust slowly drift atop a liquid core. the fossil record supports and gives credibility to the theories of continental drift and plate tectonics.

Which of the following statements best explains why there tends to be a greater number of large cities in southern africa than the east africa

As water is cooled from 4 c to 0 c its density