Correct Answer: D

Rationale: The correct answer is D: throbbing headache. Nitroglycerin is a vasodilator that relaxes blood vessels, leading to increased blood flow and reduced workload on the heart. One common side effect of nitroglycerin is a throbbing headache due to the dilation of blood vessels in the brain. This side effect is expected and usually diminishes with continued use. Explanation of other choices: A: High blood pressure - Nitroglycerin actually helps lower blood pressure by dilating blood vessels. B: GIT irritation - This is not a common side effect of nitroglycerin, as it primarily affects the cardiovascular system. C: Shortness of breathing - This is not a typical side effect of nitroglycerin, as it does not directly affect respiratory function.

Correct Answer: B

Rationale: The correct answer is B: Lung cancer. Lung cancer causes the most deaths in women due to its high mortality rate. It is often diagnosed at an advanced stage, leading to poorer outcomes. Breast cancer, although common, has a lower mortality rate compared to lung cancer. Brain cancer is relatively rare in comparison. Colon and rectal cancer, while significant, do not surpass lung cancer in terms of causing the most deaths in women.

Correct Answer: D

Rationale: The correct answer is D: Leucovorin. Leucovorin is given during methotrexate therapy to protect normal cells by acting as a rescue agent that helps to reduce the toxic effects of methotrexate. It works by enhancing the efficacy of methotrexate in cancer cells while reducing its toxicity in normal cells. Probenecid (A) is not used to protect normal cells during methotrexate therapy. Cytarabine (B) and Thioguanine (C) are other chemotherapeutic agents and are not typically given to protect normal cells during methotrexate therapy.

Correct Answer: C

Rationale: The correct answer is C: He walked home in a cold rain. Walking in cold rain can lead to vasoconstriction, which impairs blood flow, increasing the likelihood of a sickle cell crisis in individuals with sickle cell disease. This can cause red blood cells to sickle and block blood vessels, leading to pain and tissue damage. Choices A, B, and D do not directly affect the physiology of sickle cell disease and are less likely to trigger a crisis.

Correct Answer: B

Rationale: The correct answer is B: radiation therapy. Radiation therapy uses high-energy radiation to target and destroy cancer cells while minimizing damage to surrounding healthy tissues. It is a localized treatment that is effective in shrinking tumors and preventing cancer cell growth. Surgery (A) involves physically removing the tumor and surrounding tissues, while chemotherapy (C) uses drugs to kill cancer cells throughout the body. Palliative treatment (D) focuses on symptom management and improving quality of life in advanced stages of cancer. In this case, the focus is on a form of cancer therapy involving high-energy electromagnetic radiation, making radiation therapy the most appropriate choice.