Convection is a process which transfers the heat between the temperatures when fluid (i.e. liquid or gas) is in motion. Due to the presence of heat source, water temperature increases and also it will become less dense and rise. Hot air is less dense than cold. When air rises higher in the atmosphere its pressure gets down and it becomes colder.
Geography is called the mother of all sciences due to its links and influences on a range of other scientific fields including biology, math, anthropology, geology, astronomy and chemistry
Answer:
West Africa’s Great Kingdoms
For hundreds of years, trade crisscrossed West Africa. For most of that time, West Africans did
not profit much from the Saharan trade because the routes were run by berbers, a group of
people from northern Africa. Eventually, that situation changed. A succession of three great
kingdoms came to power as their people, gained control of valuable trade routes in West Africa.
Ghanawas the first of these empires, followed by the kingdoms of Maliand Songhai.
Explanation:
