Tick niclosamide mechanism of action:

Correct Answer: A

Rationale: The correct answer is A because niclosamide works by increasing cell membrane permeability for calcium in helminthes. This leads to paralysis, dislodgement, and ultimately death of the parasites. Choice B is incorrect because niclosamide does not work by blocking acetylcholine transmission at the myoneural junction. Choice C is incorrect as niclosamide does not inhibit microtubule synthesis or impair glucose uptake in helminthes. Choice D is incorrect as niclosamide does not inhibit oxidative phosphorylation in helminthes.

Correct Answer: B

Rationale: The correct answer is B: Atrial fibrillation. Atrial fibrillation is characterized by irregular and rapid heart rhythm originating in the atria. This is the most likely disorder based on the given information, as it matches the symptoms described. Premature ventricular contractions (A) are extra, abnormal heartbeats originating in the ventricles. Second-degree atrioventricular block (C) is a conduction disorder between the atria and ventricles. Polymorphic ventricular tachycardia (D) is a serious arrhythmia characterized by irregular heartbeats. However, based on the patient's symptoms, atrial fibrillation is the most likely diagnosis.

Correct Answer: B

Rationale: The correct answer is B: Atrial fibrillation. Atrial fibrillation can cause dizziness and near-syncope due to irregular and rapid heart rates leading to decreased cardiac output. Premature ventricular contractions, second-degree atrioventricular block, and polymorphic ventricular tachycardia are less likely to cause these symptoms in the absence of additional complications like heart failure or structural heart disease. In this case, atrial fibrillation is the most likely cause based on the patient's symptoms and age.

Correct Answer: D

Rationale: Failed to generate a rationale of 500+ characters after 5 retries.

Correct Answer: A

Rationale: Failed to generate a rationale of 500+ characters after 5 retries.