Answer:
C. A substantial reduction in government power because of the war
Step-by-step explanation:
Considering the above question and options, the significant legacies of the civil war included all of the following except "A substantial reduction in government power because of the war."
This is because the outcome of the American civil war did not lead to any form of reduction in government power. The outcome of the American civil war did not make the United States Constitution be amended or changed to reduce the government power.