A hapten is:

Correct Answer: C

Rationale: The correct answer is C because a hapten is a small chemical grouping that can bind to preformed antibodies but cannot induce an immune response on its own. Haptens require a carrier molecule to become immunogenic. Choice A (An epitope) is incorrect because an epitope is the specific part of an antigen recognized by an antibody. Choice B (A paratope) is incorrect as a paratope is the part of an antibody that binds to an antigen. Choice D (A carrier) is incorrect because a carrier is a molecule that can bind to a hapten to make it immunogenic.

Correct Answer: B

Rationale: The correct answer is B because the spleen does not store extra iron in ferritin. The spleen functions primarily to destroy old or defective red blood cells (choice A), break down hemoglobin (choice C), and store platelets not circulating (choice D). The spleen does not have a significant role in iron storage; that function is mainly carried out by the liver and bone marrow. Therefore, choice B is incorrect.

Correct Answer: A

Rationale: The correct answer is A: Male-to-male sexual contact. This is because statistics show that men who have sex with men (MSM) are the group most affected by new cases of HIV. MSM is considered a high-risk group due to various factors like higher prevalence of HIV within the community, higher rates of unprotected sex, and multiple sexual partners. Choice B is incorrect as heterosexual contact has a lower incidence rate compared to MSM. Choice C is incorrect as the combination of male-to-male sexual contact with injection drug use is less common than MSM alone. Choice D is incorrect because age group 25 to 29 may not necessarily be the most affected group in terms of new HIV cases.

Correct Answer: C

Rationale: The correct answer is C: "AIDS isn't transmitted by casual contact." This is the best response because it is accurate and provides the friend with correct information. HIV is not transmitted through casual contact, so the friend visiting the client is not at risk of contracting the virus. A: "Do you think that you might already have HIV?" - This response is inappropriate as it raises unnecessary concerns and does not address the friend's question directly. B: "Your immune system is likely very healthy." - This response is irrelevant to the friend's concern about contracting HIV and does not provide any information related to the risk of transmission. D: "You can't normally contract AIDS in a hospital setting." - While this statement is generally true due to universal precautions in healthcare settings, it does not directly address the friend's specific concern about HIV transmission through visiting the client.

Correct Answer: D

Rationale: The correct answer is D. Obtaining a stool culture is important to identify possible pathogens causing chronic diarrhea in a client with AIDS. This intervention will help determine the appropriate treatment and management plan. A: Positioning the client in high Fowler position is not directly related to managing chronic diarrhea in this case. B: Temporarily eliminating animal protein from the diet may not be necessary and could deprive the client of essential nutrients. C: Making sure the client eats raw fruit may exacerbate diarrhea due to the high fiber content, which could worsen the condition. In summary, obtaining a stool culture is crucial for identifying the cause of chronic diarrhea in a client with AIDS, while the other options are not directly related or may even be counterproductive.