Correct Answer: B

Rationale: The correct answer is B: Prevents postpartum hemorrhage. Methylergonovine maleate is a uterotonic medication used to prevent and treat postpartum hemorrhage by causing strong uterine contractions, which help to control bleeding after delivery. It is not used to reduce lochia drainage (choice A), decrease uterine contractions (choice C), or maintain normal blood pressure (choice D). By understanding the pharmacological action of methylergonovine maleate in preventing postpartum hemorrhage, we can confidently select choice B as the correct answer.

Correct Answer: B

Rationale: The correct answer is B: Smoking cessation. Smoking is the leading cause of lung cancer, so quitting smoking is crucial in preventing and improving survival rates. Smoking cessation reduces the risk of developing lung cancer and improves treatment outcomes. High-dose chemotherapy (A) may be part of the treatment plan, but quitting smoking is more impactful. Early bronchoscopy (C) and early detection (D) are important, but without addressing the root cause (smoking), the survival rates will not significantly increase.

Correct Answer: C

Rationale: The correct answer is C: Cryptosporidium parvum. This parasite is the most likely cause of the infection due to its presentation with watery diarrhea, abdominal cramps, and nausea after consuming contaminated water. Laboratory tests revealing oocysts in the stool sample further support this diagnosis as Cryptosporidium parvum is known to produce oocysts in the stool. Giardia lamblia (choice A) presents with similar symptoms but does not typically produce oocysts. Entamoeba histolytica (choice B) is more associated with bloody diarrhea and liver abscesses. Cyclospora cayetanensis (choice D) is also associated with watery diarrhea but is less common in this scenario. Thus, based on the symptoms and laboratory findings, Cryptosporidium parvum is the most likely culprit.

Correct Answer: D

Rationale: The correct answer is D: Teeth. Teeth are responsible for the initial mechanical breakdown of food during mastication. Step 1: Teeth use their hard surfaces to chew and grind food into smaller pieces. Step 2: This process increases the surface area of the food, making it easier for digestive enzymes to break down. Step 3: The tongue aids in moving the food around the mouth but does not break down the food mechanically. Pharynx is responsible for swallowing, not mastication. Salivary glands produce saliva that helps in the lubrication and digestion of food, but they do not directly participate in the mechanical breakdown of food.

Correct Answer: C

Rationale: The correct answer is C: Abrasion. Abrasion is the wearing away of tooth structure due to friction from external sources like toothbrushing or abrasive toothpaste. Dental caries (A) refers to tooth decay caused by bacteria. Attrition (B) is the wearing down of tooth structure due to tooth-to-tooth contact. Erosion (D) is the loss of tooth structure from acid attacks, not friction. Therefore, option C is the most fitting choice based on the description given.