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).
Nigeria is Africaâs most populous country and has one of the largest aggregation of ethnic groups in Africa. There are more than 300 Nigerian tribes and among the largest include Hausa-Fulani, Igbo, Yoruba, Ijaw, Kanuri, Annang, Tiv, Ibibio, Etsako, and Efik.here are more than 300 Nigerian tribes and among the largest include Hausa-Fulani, Igbo, Yoruba, Ijaw, Kanuri, Annang, Tiv, Ibibio, Etsako, and Efik.