View Full Document. Ultimate base level for all rivers is sea level - Longitudinal profile: way to show a riverâs overall vertical drop. Shows the elevation of its channel bottom from the headwater areas to its downstream termination (the riverâs mouth).
The population is as diverse as it is large, with some 250 ethnic groups. Nigeria's three largest ethnic groups are: Hausa-Fulani (29 percent of the population), Yoruba (21 percent) and Igbo, or Ibo (18 percent).he population is as diverse as it is large, with some 250 ethnic groups. Nigeria's three largest ethnic groups are: Hausa-Fulani (29 percent of the population), Yoruba (21 percent) and Igbo, or Ibo (18 percent).
History of Nigeria. The history of Nigeria can be traced to prehistoric settlers living in the area as early as 11000 BC. Numerous ancient African civilizations settled in the region that is today Nigeria, such as the Benin Empire, the Kingdom of Nri and the Oyo Empire.