Answer:
When European powers decided to colonize countries in Africa, they wanted to avoid conflicts in Europe over territory, because of that they decided to divide territory at the Berlin Conference in 1884-85.
European countries partitioned Africa into spheres of influences but ignored the geography, history and ethnic composition of Africa. This was the major problem for formerly colonized countries, the improper division of territory caused underdevelopment and instability in African states, many countries have ethnic wars caused by those divisions to this day.