In some regions of the world, children suffer from a protein deficiency known as kwashiorkor. This deficiency occurs when a child's diet is changed from high-protein breast milk to watery cereal. Even though the child is receiving calories, the child becomes sick and less active, and growth ceases. These symptoms are probably due to

Correct Answer: D

Rationale: The correct answer is D: a lack of essential amino acids in the diet. Kwashiorkor is a protein deficiency disease, specifically characterized by a lack of essential amino acids. Essential amino acids are necessary for proper growth and development, and when they are lacking, the body cannot synthesize important proteins. This leads to symptoms like stunted growth and decreased activity levels. Explanation of why other choices are incorrect: A: too many nucleic acids in the diet - Nucleic acids are not related to kwashiorkor. B: an overconsumption of complete protein foods - Kwashiorkor is caused by a lack of protein, not an overconsumption. C: not enough carbohydrates in the diet - While carbohydrates are important for energy, kwashiorkor is specifically a protein deficiency disease.

Correct Answer: A

Rationale: The correct answer is A: excretion. The organ shown is the kidney, which plays a vital role in filtering waste products from the blood to form urine for excretion. It is not involved in digestion (B), reproduction (C), or combating foreign microbes (D). Kidneys are specifically designed for excretion, making choice A the correct answer.

Correct Answer: B

Rationale: Region A refers to the glomerulus in the kidney, where filtration occurs. The correct answer is B because substances are filtered out of the blood into the renal tubules for further processing. Proteins being converted to urea (A) happens in the liver, not in the glomerulus. Urine storage (C) occurs in the bladder, not in the glomerulus. Water reabsorption (D) occurs in the renal tubules, not in the glomerulus. Therefore, choice B is correct for region A.

Correct Answer: D

Rationale: The correct answer is D: Carbon dioxide. The UREA breath test measures the presence of H. pylori in the stomach by detecting the breakdown of urea into carbon dioxide and ammonia by the bacteria. H. pylori produces the enzyme urease, which hydrolyzes urea into ammonia and carbon dioxide. Therefore, an increase in carbon dioxide levels indicates the presence of H. pylori. Choice A (Ammonia) is incorrect because the test does not specifically measure ammonia levels. Choice B (Urea) is also incorrect because the test measures the breakdown of urea, not the urea itself. Choice C (Hydrochloric acid) is incorrect as the test does not directly measure this acid.

Correct Answer: C

Rationale: The correct answer is C: Helicobacter pylori infection. This bacterium is the most common cause of peptic ulcer disease by causing inflammation and weakening the protective lining of the stomach or duodenum. Studies have shown a strong association between H. pylori infection and peptic ulcers. A high-fat diet (A) may exacerbate symptoms but is not the primary cause. Stress (B) and alcohol consumption (D) can worsen symptoms but do not directly cause peptic ulcers. In summary, H. pylori infection is the leading cause of peptic ulcer disease due to its ability to damage the stomach lining.