Which words best complete the lettered blanks in the two sentences below? Organic compounds, such as proteins and starches, are too __A__ to diffuse into cells. Proteins are digested into __B__ and starches are digested into __C__.

Correct Answer: C

Rationale: The correct answer is C: A-large, B-amino acids, C-simple sugars. Rationale: 1. Organic compounds like proteins and starches are too large to diffuse into cells, which is why the word "large" fits in blank A. 2. Proteins are digested into amino acids, so "amino acids" is the appropriate choice for blank B. 3. Starches are digested into simple sugars, making "simple sugars" the correct word for blank C. Summary: - Option A is incorrect because proteins are digested into amino acids, not simple sugars. - Option B is incorrect because it does not account for the specific digestion products of proteins and starches. - Option D is incorrect because starches are digested into simple sugars, not amino acids.

Correct Answer: B

Rationale: Step-by-step rationale: 1. The liver does not manufacture insulin; this function is carried out by the pancreas. 2. Storing food is a function of the liver (choice A). 3. Producing digestive juices is a function of the liver (choice C). 4. The liver has the ability to regenerate and heal itself when damaged (choice D). Summary: Choice B is incorrect because the liver does not manufacture insulin; the correct answer is B. Choices A, C, and D are incorrect as they are all functions of the liver.

Correct Answer: B

Rationale: The correct answer is B: stomach to the esophagus. The cardiac sphincter is located between the esophagus and the stomach. Its main function is to prevent the backflow of stomach contents, including acid chyme, from the stomach back into the esophagus. This helps to protect the delicate lining of the esophagus from damage due to the acidic environment of the stomach. Explanation for other choices: A: The esophagus does not connect to the mouth, so backflow from the esophagus to the mouth is not a concern. C: The duodenum is the first part of the small intestine and is located after the stomach, so backflow to the stomach is not controlled by the cardiac sphincter. D: The colon is part of the large intestine and is not directly connected to the small intestine, so backflow from the colon to the small intestine is not relevant to the function of the cardiac sphincter.

Correct Answer: C

Rationale: The correct answer is C: mouth. Starch digestion begins in the mouth with the action of salivary amylase, an enzyme that breaks down starch into maltose. This process initiates the breakdown of complex carbohydrates into simpler sugars. The stomach (A) primarily digests proteins, the small intestine (B) further breaks down carbohydrates, proteins, and fats, and the esophagus (D) is a passageway for food to travel from the mouth to the stomach. Hence, the mouth is where the digestion of starch begins due to the presence of salivary amylase.

Correct Answer: C

Rationale: The correct answer is C: gall bladder. The gall bladder stores and releases bile produced by the liver, which aids in the digestion of lipids by emulsifying fats. This process breaks down large fat globules into smaller droplets, increasing the surface area for enzymes to act upon. Salivary glands (choice A) produce saliva that contains enzymes for carbohydrate digestion. The stomach (choice B) primarily digests proteins through the action of gastric enzymes. The large intestine (choice D) mainly absorbs water and electrolytes, not involved in lipid digestion.