What benefit is not provided by africa's rivers

Navigation.

Explanation:

As most of them meander too much, have too many falls, and are swampy and narrow. Only some are navigable up to a certain extent as to there mouths but most of them are not developed for the purpose of the navigation across the nations and the countries. Due to the prevalence of the thick and dense forest of the lands many river navigation systems has not got much of the investment form the government of the African nations.

It's probably because some types of violets are blue

Population of this city. also, look for information on available public transit, bike-sharing, and other commuting options. use the information you find and write about it promoting alternative transportation