Correct Answer: B

Rationale: The correct answer is B. Raloxifene, such as Evista, works by decreasing bone resorption and increasing bone density. This medication is beneficial in the prevention and treatment of osteoporosis by slowing down the breakdown of bone tissue, thereby reducing the risk of fractures. Choices A, C, and D are incorrect because raloxifene does not directly stimulate the formation of new bone, increase calcium absorption in the intestines, or increase the excretion of calcium through the kidneys.

Correct Answer: A

Rationale: Astrocytes play a crucial role in supporting and nourishing neurons by providing metabolic support, maintaining the blood-brain barrier, and regulating the chemical environment of the brain. While astrocytes are essential for brain function, they are not neurons and do not transmit electrical signals (Choice B). Astrocytes are not primarily involved in immune responses in the brain (Choice C) or in regulating blood flow in the brain (Choice D), although they indirectly influence blood flow through their support functions.

Correct Answer: B

Rationale: The correct answer is B. Medroxyprogesterone should be taken at the same time each day to maintain consistent hormone levels and effectiveness. Choice A is incorrect because medroxyprogesterone does not necessarily need to be taken with food. Choice C is incorrect as it is typically prescribed continuously rather than intermittently. Choice D is incorrect because patients should not stop the medication if side effects occur without consulting their healthcare provider.

Correct Answer: A

Rationale: Raloxifene decreases bone resorption, which helps to maintain or increase bone density, making it effective in the prevention and treatment of osteoporosis.

Correct Answer: D

Rationale: A rash from poison ivy is an example of a type IV hypersensitivity reaction. Type IV hypersensitivity reactions are delayed cell-mediated immune responses involving T cells. This type of reaction is characterized by a delayed onset, typically occurring 48-72 hours after exposure to the antigen. Choice A, Type I hypersensitivity reactions, are immediate hypersensitivity reactions mediated by IgE antibodies. Choices B and C, Type II and Type III hypersensitivity reactions, involve antibody-mediated cytotoxicity and immune complex deposition, respectively, which are not characteristic of poison ivy-induced rashes.