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 ranks number 7 in the list of countries (and dependencies) by population. The population density in Nigeria is 211 per Km2 (545 people per mi2). The total land area is 910,802 Km2 (351,662 sq. miles) 49.9 % of the population is urban (95,764,092 people in 2017) The median age in Nigeria is 18 years.