The major natural estrogens produced by women are following EXCEPT:

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: 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.

Correct Answer: A

Rationale: The correct answer is A: TRUE. Gemfibrozil, a fibric acid derivative, can potentiate the effects of antihypertensives leading to dizziness and syncope due to its potential to lower blood pressure. This interaction is well-documented and pharmacologically plausible. It is important to monitor patients closely when using gemfibrozil with antihypertensives to prevent adverse effects. Choices B (FALSE), C (All), and D (None) are incorrect as they do not accurately reflect the potential drug interaction between gemfibrozil and antihypertensives.

Correct Answer: D

Rationale: The correct route of administration for 1,25-dihydroxyvitamin D3 (calcitriol) is oral (Choice D). This is because calcitriol is a form of vitamin D that is typically taken orally for absorption in the intestine. When taken orally, it undergoes hepatic and renal hydroxylation to its active form. Subcutaneous (Choice A), intravenous (Choice B), and intranasal (Choice C) routes are not typically used for administering calcitriol as they may not provide the necessary absorption and metabolism required for its activation in the body.