Was the system of alliances the only reason other nations entered the war?

yes because The alliances system meant that a local conflict could easily result into an intimidating global one. The overall cause of World War was the assassination of Archduke Franz Ferdinand. Nationalism was a great cause of World War one because of countries being greedy and not negotiating

Explanation:

we will reach the goal of freedom in birmingham and all over the nation,

d. migration of french settlers into english colonies