15. What was the sin whereby our first parents fell from the estate wherein they were created?

Gen 3.6
And when the woman saw that the tree was good for food, and that it was pleasant to the eyes, and a tree to be desired to make one wise, she took of the fruit thereof, and did eat, and gave also unto her husband with her; and he did eat. V7. And the eyes of them both were opened, and they knew that they were naked. V8. And Adam and his wife hid themselves from the presence of the Lord God amongst the trees of the garden.