Answer: a Ethnic groups were fighting with each other for control.
Explanation:
The fighting in Bosnia-Herzegovina came about as Yugoslavia, a multinational country, was disintegrating. Fighting broke out between different groups who wanted to control the others.
The most prominent were the Serbians who wanted to play a leading role in the country. The Serbians formed a large group in Bosnia and wanted Bosnia to be part of Serbia and were willing to fight for that, which they did. This led to the Bosnian war and saw some atrocities committed by the belligerents included ethnic cleansing.