Justify your answer with relevant examples providing a point, explanation and evidence clearly. I don't know how to answer in that format which we're using at school so, much help would be appreciated!
I do not think the witches are responsible for Macbeth's transformation, because I do not really think he underwent a transformation. Macbeth was always passionate and lacking in impulse control. It made him a good soldier. When someone told him he could have something, he wanted it. This is what happened with the witches. Once they told him he’d be king, he thought he should be. All they did was give him a little push.
This is the harvest theme in the play--the witches plant the seed, Lady Macbeth waters and suns it, and Macbeth the Murderer is born from it. His ambition is nurtured until his downfall, and even after the murder of Duncan which puts Macbeth on the throne, the witches continues to mislead him with false apparitions. They knew how he would interpret them (since that is what he wants to see happen) and that he wouldn't consider any other possibilities. This shortsightedness causes Macbeth's downfall as he is overconfident of his success.
The witches plant the seed of hope in Macbeth's mind, but he's the one who--to continue the metaphor--cultivates it to full growth.