Hormones from the stomach are sent to the brain to tell you when to stop eating
This could be true. Depends on how much sleep the person missed.
I'm sure the answer you are looking for is specific to your class, but I would say that the nurse should provide something like, "The tumor is most likely benign, but until we test further, we can't know if it's malignancy."
Vitamins are chemicals essential to all cellular activity.
A student slips on the ice in front of school and sprains his ankle.