Correct Answer: D

Rationale: Smoking is a major risk factor for atherosclerosis. It significantly contributes to the buildup of plaque in the arteries and thereby increases the risk of cardiovascular diseases. On the other hand, exercise is generally beneficial for cardiovascular health and is not a risk factor for atherosclerosis. Excessive sun exposure and insufficient vaccinations have no established links to atherosclerosis, making them incorrect options for this question.

Correct Answer: A

Rationale: Amino acids are the correct answer because they are the building blocks of proteins that the body absorbs after digestion. Pepsin, choice B, is incorrect as it is an enzyme that aids in the digestion of proteins, not the absorbable unit of them. Choices C and D, glucose and sucrose, are wrong because they are types of sugars, not proteins.

Correct Answer: B

Rationale: The correct answer is B, Altered taste sensation. The use of antibiotics is known to cause changes in taste sensation as a side effect, especially when used to treat H. pylori infections. Hemoptysis (Choice A) refers to coughing up blood, and while it can be a symptom of various conditions, it is not typically associated with the use of antibiotics. Flatulence (Choice C) and bloody stools (Choice D) can also occur as gastrointestinal complications, but they are not the most likely side effect when treating H. pylori with antibiotics. Therefore, choices A, C, and D are incorrect.

Correct Answer: D

Rationale: Carbohydrates, fats, and proteins are the three macronutrients that provide energy (calories) to the body. Carbohydrates are the body's primary source of energy, fats act as a secondary source when carbohydrate energy is exhausted, and proteins are used for energy when carbohydrate and fat sources are low. Choice D, Water, is essential for the body's functions, but it does not provide energy.

Correct Answer: B

Rationale: All the statements above are accurate about oral exposure to fermentable carbohydrates, except for option B. In fact, longer exposure to these carbohydrates decreases the opportunity for remineralization. This is because the process of demineralization, in which minerals are lost from the tooth enamel, is sped up by the presence of fermentable carbohydrates. The Stephan curve (option C) is a graph that demonstrates how the pH of dental plaque changes after a sugar rinse, usually dropping (becoming more acidic), which can lead to enamel decalcification. Option D is also accurate, as a pH of 5.5 or lower is the critical point at which enamel starts to decalcify.