What cause made feudal wars?

the central government of Europe collapsed. As the Vikings invaded western European kingdoms, local nobles took over the duty of raising armies and protecting their property. Power passed from kings to local lords, giving rise to a system known as feudalism.

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explanation:

nuclear fission produces the atomic bomb, a weapon of mass destruction that uses power released by the splitting of atomic nuclei the fighting in iwo jima and okinawa affected the allies' pacific strategy because truman decided to drop the atomic bomb on mainland japan.