<p>Plagarism is a serious problem. Why it happened, how it happened, is for you to discuss with them and they can decide whether they believe you or not and what the consequences will be. It is sometimes very difficult to separate out purposeful plagarism (which amounts to cheating and claiming others’ work as their own) from forgetting to cite or citing inappropriately. We can’t possibly know the details of your situation. I would hope they would go far lighter than suspension or cut you slack with a first offense and make it educational rather than punitive, but that is just my personal opinion. </p>
<p>If you ask me, I think whether or not the consequences for plagarism is consistently applied across teachers is not remotely relevant to your argument. If they have taught you the rules, tell you there will be consequences and you subsequently break the rules, you are responsible. People do things all the time- purposefully and inadvertently- that violate particular rules. Sometimes you get caught and have a consequence, sometimes you do not. It just goes like that.</p>