1. C.
2. C.
3. B.
4. C.
5. C.
6. B.
7. C
8. D.
9. A.
10. C.
11. The body uses food to absorb the nutrients needed for the cells and tissues in our bodies. Water is used for chemical reactions, carbohydrates are sugars used for energy, fats are used for insulation and proteins are used for growth and repair.
12. Carbohydrates provide the body with energy.
13. Proteins aid in growth and repair in the body. They also provide the body with 8 essential amino acids that the body cannot produce by itself.
14. The Food Guide Pyramid classifies foods into six groups and indicates how many servings from each group should be eaten every day in order to keep a balanced diet.
15. Swallowed food does not enter the airway leading to the lungs because as the food is swallowed, a flap of connective tissue closes over the opening of the trachea to prevent food from clogging these airways.
16. During digestion, enzymes such as amylase break chemical bonds between the sugar monomers in starches. Digestive enzymes also break down foods and make the nutrients available to the body.
17. Mechanical digestion includes the muscles of the stomach contracting to mix stomach fluids and food which produces a mixture known as chyme. Chemical digestion includes the production of acids that aid the digestion and absorption of food.
18. In the stomach, hydrochloric acid makes to contents of the stomach extremely acidic. Pepsin breaks proteins into smaller pieces and it works best under the acidic conditions present in the stomach. The combination of these two begins the process of protein digestion.
19. Recently, scientists have discovered that peptic ulcers are usually caused by the bacterium Helicobacter pylori. Doctors all over the world now understand that many peptic ulcers are caused by an infectious disease that can be cured.
20. The pancreas is a gland that serves three important functions including producing hormones to