Zhenya raised her hand, and waited to say "Professor Lafay an allergy is something which causes someone to become hypersensitive. By that, their immune system begins a process to get rid of the allergy. For some reason the body has told itself that a certain thing is no good, which is where the immune system comes in. An allergen is usually something that others have no reaction to at all, but its just the types of antibodies the person has, and also what you said, it is related to what the person is exposed to which can develop into a reaction," she said. She had learned a lot about allergens and the different types of reactions someone can have when she saw a friend collapse and almost die when she unknowingly ate a peanut. So, Zhenya asked her father to explain it to her. She really felt bad for some of the other students.