Question

The naval blockade of the south was designed to prevent?

Answer 1

All of the above. Which was Import of ammunition, Import of weapons, Export of cotton. (APEX class ;)

Answer 2

The blockade was supposed to prevent the South from getting resources and support from other countries who would support it such as those in Europe who were ready to recognize it as independent and help it if it meant that in the long run it would help them by weakening the Union.