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).
1 Nigeria's population is equivalent to 2.46% of the total world population. 2  Nigeria ranks number 7 in the list of countries by population. 3  The population density in Nigeria is 193 people per Km2.4  51% of the population is urban (91,834,051 people in 2014). 5  The median age in Nigeria is 17.8 years. Nigeria ranks number 7 in the list of countries by population. 2  The population density in Nigeria is 193 people per Km2. 3  51% of the population is urban (91,834,051 people in 2014).