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).
Ethnicity is one of the keys to understanding Nigeriaâs pluralistic society. It distinguishes groupings of peoples who for historical reasons have come to be seen as distinctiveâby themselves and othersâon the basis of locational origins and a series of other cultural markers.thnicity is one of the keys to understanding Nigeriaâs pluralistic society. It distinguishes groupings of peoples who for historical reasons have come to be seen as distinctiveâby themselves and othersâon the basis of locational origins and a series of other cultural markers.