vitamins and health class

In health class today, we were learning about vitamins and how they help our bodies. After learning about the second one which may help prevent cancer, this started a conversation about cancer. Some of them were saying, "What is cancer?" Before I could answer, one girl piped up, " I know -- cancer is when your arms start shaking and your eyes roll back and you swallow your tongue!" I was a little confused at first then said, "um, no . . . that's a seizure."