The poor transport and communication infrastructures in Africa such as lack of good roads, railways postal services.
Europeans had limited knowledge of Africa resources especially those in the interior
Europeans were also ignorant of the fertile nature of the Africans soil which could be use for plantations.
The supply of raw materials from other European colonies like; Asia, Latin America was large enough to support the Europeans.
The low level of industralisation in Europe and low levels of production made the Europeans not to desire extensive market. This explain their reluctance.
