Explain two christian beliefs about the causes of sin?

According to Christian belief, sin separates humans from God, bringing lasting punishment. God gave humans free will so it is up to humans to decide for themselves how to behave, ie in an evil or good way. Many Christians believe all humans are descended from Adam and Eve, which means that they all have the ability to disobey God. Original sin occurred when Adam and Eve were tempted and committed the first (original) sin.