Which Was a Greater Source for the Nigerian Civil War?

Which was a greater source for the Nigerian civil war also called the Biafran war, Amalgamation or Tribalism?The war took place at the 'blight of biafra' and was between the Nigerian armed forces and the Biafran soldiers. The Biafrans were initially a part of Nigeria until, May 30 19671 when the leader of the eastern part of Nigeria, citing the northern massacres and fearing genocide proclaimed a seccession of the south-eastern region from Nigeria as a Republic of Biafra. The head of the Federal Military Government in Nigeria then attacked the southern and eastern region therefore the Biafran war.
This has always been blamed on the amalgamation of the country as citizens of the country have always complained that the British, knowing nothing of the cultural and ethnic groups simply drew lines and borders and gave those regions surrounded by those borders names and expected them to be a country2.
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