I think your tutors have been very clever here by chosing this question as it means that no-one on here can give you the answer. It all comes down to the treatment you choose and the products that you use, so I think you are on your own on this one.
Your course books will give you the answers to this question,
as for the key ingredients read the containers your products are in or go to the web site that provides them,
they will have an explanation of what their products do hth
sorry hun but we are not allowed to give you the answers only point you in the right direction to find them