19. The respiratory system allows us ____ in vital oxygen and expel carbon dioxide in a process we call breathing.
A. take B. to take C. taking D. taken
20. The urinary system helps eliminate a waste product called urea ____ the body, which is produced when certain foods are broken down.
A. of B. off C. from D. out
21. The skin, or integumentary system, is the body's largest organ, which protects us from the outside world, and is our first defense ____ bacteria, viruses and other pathogens.
A. of B. upon C. to D. against
22. Our bodies are supported by the skeletal system, which consists of 206 bones ____ tendons, ligaments and cartilage.
A. that connect to B. that are connected by C. which connects to D. which is connected by
23. The job of ____ circulatory system is to move blood, nutrients, oxygen, carbon dioxide, and hormones, around the body.
A. a B. the C. its D. whose
24. The digestive system consists of a series of ____ organs that together, allow the body to break down and absorb food, and remove waste.
A. connect B. connecting C. connected D .connective
25. The pharmaceutical industry would lose billions in profits if people relied on the natural healing ____ of water rather than expensive and toxic drugs.
A. features B. characteristics C. properties D. matters
26. Once you're dehydrated, you also become mineral ____, which is the foundation for all diseases in the human body.
A. deficient B. deficiently C. deficiency D. deficiencies
27. The lymphatic system includes lymph nodes, lymph ducts and lymph vessels, and also ____ a role in the body's defenses.
A. takes B. does C. acts D. plays
28. The nervous system controls both voluntary action (like conscious movement) and involuntary actions (like breathing), and sends ____ to different parts of the body.
A. signs B. signals C. signatures D. signers
29. A: "I need to stop eating such unhealthy foods."
B: “____”
A. That sounds delicious and nutritious.
B. I know what you mean. I've started eating better myself.
C. I mainly eat baked chicken, because there's not a lot of fat.
D. Are you sure that's how you want me to make it?
30. A: "Doctor, can you give me some suggestions on how to stay healthy?"
B: “____”
A. Well, first of all, you need to make sure that you eat the right foods.
B. It is very confusing to know what to eat.
C. As long as you don't overdo it, a glass of wine a day should be OK.
D. If you smoke, you need to stop.
