I suspect this a college question, and wonder whether you have a textbook with a section on health and safety?
Does your teacher want you to think about the answer, research it, or just have you recite it parrot fashion? I'm not sure whether asking UKPF for the answer counts as research or copying though, which is why I'm reluctant to start to discuss.
When I was at college, one answer offered by one of my peers was 'laugh?', by the way.