paragraph: Michelle was riding her scooter. She hit a hole in the street. She started to lose control of her scooter. She thought she would fall. In the blink of an eye, she shifted her weight. This quick action helped her to keep her balance. Her heart was pounding. The good news is that she did not get hurt. How was she able to react so quickly? Michelle can thank her nervous system. The nervous system does not work alone. It works with the endocrine system. Together, they control all the other organ systems. The nervous system sends one type of signal. The nervous system sends electrical pulses. The endocrine system sends another type of signal. These chemical signals are called hormones. Hormones tell other body parts that a change is needed. 
question: Which two systems control all other organ systems?
answer: Organ system