Immune system is the integrated body system of organs, tissues, cells, and cell products that differentiates self from nonself and neutralizes potentially pathogenic organisms or substances. This consideration is:

Correct Answer: A

Rationale: The statement accurately describes the immune system, making choice A true. The immune system indeed consists of organs, tissues, cells, and cell products that distinguish self from nonself and combat harmful pathogens. Choice B is incorrect as the statement is true. Choice C is incorrect as it implies all choices are correct, which is not the case. Choice D is incorrect as the statement is true, so it is not "none."

Correct Answer: A

Rationale: Step 1: Identify the antienzyme that inhibits proteolysis. Proteolysis is the breakdown of proteins into smaller peptides or amino acids by proteolytic enzymes. Step 2: Contrical is a proteolysis inhibitor that specifically inhibits trypsin, a digestive enzyme that breaks down proteins in the small intestine. Step 3: Sulbactam is a beta-lactamase inhibitor used in combination with antibiotics to prevent bacterial resistance. Step 4: Aminocaproic acid is a fibrinolysis inhibitor used to prevent excessive blood clot breakdown. Step 5: Disulfiram is an alcohol deterrent that inhibits aldehyde dehydrogenase, not proteolysis. Summary: Contrical (Choice A) is the correct answer as it directly inhibits a proteolytic enzyme involved in protein breakdown. Sulbactam, aminocaproic acid, and disulfiram do not target proteolysis enzymes.

Correct Answer: B

Rationale: Rationale: 1. Probucol does not stimulate the rate of clearance of LDL by receptor-mediated pathways. 2. Probucol works by increasing HDL levels and reducing LDL oxidation. 3. Therefore, the statement that Probucol stimulates LDL clearance is false. 4. Choice B is correct as it accurately reflects the mechanism of action of Probucol. Summary: - Choice A is incorrect as Probucol does not stimulate LDL clearance. - Choice C is incorrect as not all statements are true. - Choice D is incorrect as the statement is false.

Correct Answer: A

Rationale: Step-by-step rationale for correct answer (A): 1. Dihydrotachysterol is a vitamin D analog used to treat parathyroid hormone resistance. 2. Parathyroid hormone resistance leads to impaired calcium absorption and bone mineralization. 3. Dihydrotachysterol helps increase calcium absorption and bone mineralization in these patients. Summary of incorrect choices: - B: Paget's disease is typically treated with bisphosphonates or calcitonin, not dihydrotachysterol. - C: Increased osteolysis is not a direct indication for dihydrotachysterol administration. - D: Hypophosphatemia is usually treated with phosphate supplements, not dihydrotachysterol.

Correct Answer: A

Rationale: Step-by-step rationale for why choice A (Hydrochlorothiazide) is correct: 1. Hydrochlorothiazide is a thiazide diuretic that decreases urine volume by increasing water reabsorption. 2. In nephrogenic diabetes insipidus, the kidneys are unable to respond to antidiuretic hormone (ADH), causing excessive urine production. 3. Hydrochlorothiazide can help reduce urine output by enhancing water reabsorption, thus alleviating symptoms of nephrogenic diabetes insipidus. Summary of other choices: - Choice B (Amiloride) is a potassium-sparing diuretic that does not directly address the underlying mechanism of nephrogenic diabetes insipidus. - Choice C (Both of the above) is incorrect as only Hydrochlorothiazide is indicated for treating nephrogenic diabetes insipidus. - Choice D (Neither of the above) is incorrect as Hydrochlorothiazide is indeed