20. How does the nervous system help our body? A. Nervous system receives and transports messages to the body. B. Nervous system gives support and structure to the body. C. Nervous system transports blood to the different parts of the body D. Nervous system expels waste and toxins from the body. 21. Why do you move your hand away when you accidentally touch hot objects? A. The moving of hand is a voluntary action. B. The message travels fast because of the heat. C. The muscles react fast before the message reached the brain. D. The message to and from the brain travels fast because of the nerves. 22. Why is brain important in the nervous system? A. Because it is the control center of the body. B. Because it pumps blood to the different parts of the body, C. Because it collects and carry nerve impulses. D. Because it controls our emotions. 23. What is the work of urinary bladder in the excretory system? A. It filters and cleans the blood to remove waste substance from the body, B. It is a passage of liquid waste from the kidney. C. It helps regulate the outflow of urine. D. It is a temporary storage of urine before going out of the body 24. What will happen to a person who has only one kidney? A. The person will suffer because his/her blood will not be filtered. B. The persons waste will not be eliminated from the body. C. The person's blood will still be filtered from the body, D. The person will get sick and die. 25. How do kidneys play an important role in the excretory system? A. Kidney digests food that enters the body. B. Kidney expels solid waste from the body, C. Kidney filters wastes and toxins from the body. D. Kidney secrets sweat from the body.​