The enzyme pepsin is produced in the cells of the stomach but not in the cells of the small intestine. The small intestine produces a different enzyme, trypsin. The reason that the stomach and small intestine produce different enzymes is that the gene that codes for pepsin is

Answer Explanation

B) lettuce-and-tomato salad

- Correct: Lettuce-and-tomato salad would provide the most roughage for the body. Roughage, also known as dietary fiber or bulk, refers to the indigestible portion of plant foods that adds bulk to the stool and helps regulate bowel movements. Lettuce and tomatoes are both rich sources of dietary fiber. Lettuce, especially varieties like romaine or leaf lettuce, contains cellulose and other insoluble fibers, while tomatoes contain soluble fibers like pectin. Consuming a salad made of lettuce and tomatoes would provide a significant amount of roughage to the body, promoting digestive health and regular bowel movements.

A) baked fresh fish

- Incorrect: Fish does not contain significant amounts of dietary fiber. While fish is a valuable source of protein and other nutrients, it is not a source of roughage.

C) fried chicken breast

- Incorrect: Fried chicken breast does not contain significant amounts of dietary fiber. Additionally, frying can add unhealthy fats and calories to the chicken breast, further reducing its nutritional value in terms of roughage.

D) milkshake

- Incorrect: Milkshakes are typically made with milk, ice cream, and flavorings, none of which provide dietary fiber. In fact, milkshakes are generally low in fiber and may contain high amounts of sugar and fat, making them poor choices for increasing roughage intake.

Answer Explanation

A) The stomach - This is an organ of the digestive system. It plays a crucial role in breaking down food through the secretion of gastric juices, which contain enzymes and acids to begin the process of digestion. Therefore, option A is correct.

B) The mouth - The mouth is also an organ of the digestive system. It is where the process of digestion begins, as it is responsible for chewing and breaking down food into smaller pieces. Additionally, saliva produced in the mouth contains enzymes that start the chemical breakdown of food. Therefore, option B is correct.

C) The intestines - Both the small intestine and the large intestine are essential organs of the digestive system. The small intestine is where most of the absorption of nutrients from food occurs, while the large intestine absorbs water and salts from the material that has not been digested. Therefore, option C is correct.

D) The heart - The heart is not an organ of the digestive system. Instead, it is a part of the circulatory system responsible for pumping blood throughout the body. While the circulatory system works in conjunction with the digestive system to transport nutrients absorbed from the intestines to various tissues and organs, the heart itself is not directly involved in digestion. Therefore, option D is incorrect.

Answer Explanation

D) pancreas and the gallbladder

- Correct: Both the pancreas and the gallbladder release digestive secretions directly into the small intestine. The pancreas secretes pancreatic enzymes (such as amylase, lipase, and proteases) into the small intestine to aid in the digestion of carbohydrates, fats, and proteins. The gallbladder stores bile produced by the liver, which is released into the small intestine to aid in the emulsification and digestion of fats.

A) salivary glands and the pancreas

- Incorrect: While the pancreas releases digestive secretions directly into the small intestine, the salivary glands secrete saliva into the mouth, which contains enzymes (such as amylase) that begin the digestion of carbohydrates. Salivary glands do not release digestive secretions directly into the small intestine.

B) gall bladder and the lacteals

- Incorrect: The gallbladder stores bile produced by the liver, which is released into the small intestine to aid in fat digestion. Lacteals are lymphatic vessels found in the villi of the small intestine and are involved in the absorption of fats, but they do not release digestive secretions directly into the small intestine.

C) villi and the salivary glands

- Incorrect: Villi are finger-like projections in the small intestine that increase the surface area for absorption of nutrients but do not release digestive secretions directly into the small intestine. Salivary glands secrete saliva into the mouth to initiate the digestion of carbohydrates but do not release digestive secretions directly into the small intestine.