the American civil war was caused by a struggle for economic power between the southern and northern states, to what extent do you agree with this statement

If you are taking AP, you need to know that every question they ask should be qualified. So you need to provide arguments for both sides. Although blah blah blah as shown by/ because of , overwhelming blah blah blah as shown by/ because of

So you could say something like this: Although the struggle for economic power between the southern and northern states had some influence on the start of the Civil War as shown by differences in Southern King Cotton and Northern Industry, it was ultimately the institution of slavery that resulted in the war, as shown by conflicts such as the Kansas-Nebraska Acts and the John Brown raids.

Although this is really clunky, you could tweak it and make it works. I hope this helps you for your final or for your essay :)

b) the confederacy had to pay all union war expenses.

was found at b)south carolina