Final exams are around the corner,and you have been studying late every night and up again early in the morning.You are anxious and stressed because you really want to achieve an A+ in your biology course.The day before the final exam,you begin to feel fatigued and have a sore throat.All of the following are potential reasons that you are becoming ill except
A)lack of rest. B)poor nutrition. C)increased stress level. D)immune system disruption. E)moderate exercise.