Development (3) Communication (3) Wealth (3) Time (3) Human beings (3) Example (3) Earth (Planet) (3) Cities and towns (3) Biotic communities (3) Sources (3) Sources (3) Remote sensing (3) Sources (3) Richesse (3) Information (3) Terre (3) Écosystèmes (3) Homme (3) nombre (3) terre (3) Sénégal (2) Doors (2) Employment (2) Costs (2) Cartography (2) Diseases (2) Census (2) Census (2) Democratization (2) City dwellers (2)