Name 3 problem that led to the Civil War.

the only answer is the right to leave the union

While slavery is thought to be the cause, there was a resolution to that offered which the southern states declined after Lincoln was elected. Prior ot this time there was a ongoing dispute that started before the Revolutioary war. This was basically the Federalists who wanted a strong Federal govenment and the supporters of states rights. This had much to do with the the way th3e constituion was written and the compromises made. What the constitution left unclear was whether a state could secede from the union. Prior to Lincoln becoming president, it was thought that any state could secede and pervious secession threats were dealt with by compromise. Lincolna nd Federalism of course won. Before that we were United States(seperate enities). After that we were THE United States (1 entity).
Second was probably the invention of the cotton gin. This gave the South a large increase in wealth. This increase in wealth gave them encouragement that they did not have to put up with the poor deal they got at the Constitutional Convention. Rather than having battles and duels in congess, they could have what they had wanted after the revolution which was mainly an effort by the business men of the North. The cotton gin also increased the value of slavery which further divided the two groups.
The third was a conflict of cultures. Most of the southerners were not slave holders. However they were independent agrarians. They wanted a life style of selfsufficency in their own lives, and their communities lives. they believed in equality which Jefferson had stood for in the beginning They were suspicious of rules and laws enacted by strangers in the capital. The northerns were becoing industrial which involved classes. Their were the company leaders and the workers and the imigrants and each had their own social strata. For them it was natural to have a government someplace telling them what to do. The southerners could not accept this ruling class. Seeing they were different they wanted the government they needed.
Still the root cause was the election of Lincoln. Lincoln was the one who would not let the states secede. Once a reknown Federalist was elected, the South could not accept that so they did secede. If anyone else had been elected president, there would not have been a war even though there may have been a secession.
Of course this in only my opinon and probably not the test book answer you want. I am just a man who thinks for himself and does not memorize other peoples thoughts.
Anyway, I hope there may be some value in my answer.

imbalance between agricultural and industrial sectors of the economy

Lazy white southerners
Lack of respect for basic human rights by lazy white southerners
The hubris of lazy white southerners

in the USA? abolishment of slavery in the north. I think that is one?

slavery, states rights and col. sanders