An endogenous vasoconstrictor that can stimulate aldosterone release from suprarenal glands:

Correct Answer: C

Rationale: The correct answer is C: Angiotensin II. Angiotensin II is an endogenous vasoconstrictor that can stimulate aldosterone release from the suprarenal glands. It is formed from the conversion of Angiotensin I by Angiotensin-converting enzyme (ACE). Angiotensinogen (choice A) is the precursor protein that is converted to Angiotensin I. Angiotensin-converting enzyme (choice D) is responsible for converting Angiotensin I to Angiotensin II, not for directly stimulating aldosterone release.

Correct Answer: C

Rationale: Rationale: 1. Ethinyl estradiol is a synthetic estrogen, not a natural estrogen. 2. Estradiol, estrone, and estriol are natural estrogens produced by women. 3. Ethinyl estradiol is commonly found in birth control pills. 4. Estrogen-17β is the form of estrogen predominantly produced by women. Summary: Ethinyl estradiol is the correct answer because it is a synthetic estrogen, unlike estradiol, estrone, and estriol, which are natural estrogens produced by women.

Correct Answer: C

Rationale: Rationale: Aspirin is not indicated for relieving severe visceral pain like myocardial infarction, cancer pain, renal or biliary colic. Aspirin is primarily used for its anti-inflammatory and antiplatelet effects, making choices A, B, and D correct indications. Choice C is incorrect as aspirin is not a preferred analgesic for visceral pain.

Correct Answer: D

Rationale: The correct answer is D: All of the above. Monoclonal antibodies are laboratory-produced molecules designed to target specific antigens. Trastuzumab targets HER2 protein in breast cancer, Rituximab targets CD20 antigen in B-cell lymphoma, and OKT-3 targets CD3 antigen in organ transplant rejection. Therefore, all choices A, B, and C are examples of monoclon, antibodies, making option D the correct answer. The other choices (A, B, C) are incorrect because they are individual examples of monoclonal antibodies, but the question asks for all correct options.

Correct Answer: D

Rationale: Step-by-step rationale for why Vitamin C (Choice D) is the correct answer: 1. Vitamin C is essential for collagen synthesis, which is crucial for maintaining the integrity of gum tissues. 2. Deficiency of Vitamin C leads to weakened collagen, causing symptoms like loosening of teeth, gingivitis, and hemorrhage. 3. Vitamin K (Choice A) is important for blood clotting, not directly related to gum health. 4. Vitamin B1 (Choice B) is essential for energy production, not directly linked to gum health. 5. Vitamin B6 (Choice C) is involved in various metabolic processes, but not specifically related to gum health. Summary: The correct answer is Vitamin C (Choice D) because it is directly linked to maintaining healthy gum tissues by supporting collagen synthesis. Choices A, B, and C are incorrect as they are not directly associated with the symptoms of loosening of teeth, gingivitis, and hemorrhage.