Answer:
The civil war was caused because Charles the I was a greedy man and wasn't the best English ruler. The big reasons why the Civil War started was because of: Money, Power and religion.
Money: Charles spent too much money on himself. Soon enough he needed more money and makes people pay ship tax. People who refused were put in prison.
Religion: Charles believed Kings get their power from God and must be obeyed. Charles married a Spanish Catholic (henrietta Maria. People thought Catholics could take over, Charles made William Laud the Archbishop, Laud didn't like puritans. Not liken Puritans he introduced statues, music and candles everything a Puritan hates. Laud's changes are forced upon Catholic churches and most Scots were Puritan. In 1639 the Scots attacked England because they didn't agree with the religious changes. Charles had to surrneder having no money or army to fight.
Power: Charles ruled without Parliament, but he soon needed money! Charles asked the Parliament for money to fight the Scots. Strafford is executed by order of the long Parliament and Laud is put in prison. Earl of Strafford rules Ireland for Charles. He was very unpopular with the Irish and the long Parliament.
These are the three main reasons for the English Civil War.
Enjoy :)