Which historical event provides evidence for immune adaptation?

Correct Answer: B

Rationale: The Black Death caused by Yersinia pestis is the correct answer because it led to immune adaptation in survivors. Yersinia pestis triggered the body to develop immunity. The Spanish flu pandemic, HIV/AIDS epidemic, and eradication of smallpox did not directly result in immune adaptation like the Black Death. The Spanish flu and HIV/AIDS were caused by viruses that did not lead to long-term immunity, and smallpox eradication was achieved through vaccinations, not natural immune adaptation.

Correct Answer: C

Rationale: The correct answer is C because a cell's response to a specific cytokine is determined by the specific cytokine receptors expressed on the cell. Cytokine receptors are proteins on the cell surface that bind to specific cytokines, triggering intracellular signaling pathways that lead to various cellular responses. The amount of antigen present (A) is related to the initiation of the immune response but not the cell's response to cytokines. The type of pathogen encountered (B) may influence the overall immune response but not the specific response to cytokines. The tissue location of the immune cell (D) can affect the types of cytokines present in the microenvironment but does not directly determine the cell's response to a specific cytokine.

Correct Answer: B

Rationale: The correct answer is B because innate immunity instructs and activates adaptive immunity. Innate immunity serves as the first line of defense against pathogens, recognizing and initiating a response to pathogens. It then communicates with adaptive immunity, providing signals and antigens to activate and guide the adaptive immune response. This collaboration is crucial for the effective elimination of pathogens. Choices A, C, and D are incorrect because innate immunity does not suppress, replace, or function independently of adaptive immunity; rather, they work together in a coordinated manner to provide a comprehensive immune response.

Correct Answer: B

Rationale: Rationale: C1q is a component of the classical complement pathway, crucial for immune complex clearance. Its deficiency is associated with SLE due to impaired immune complex removal, leading to autoantibody deposition and inflammation. Cancer, HIV/AIDS, and COPD are not directly linked to C1q deficiency.

Correct Answer: C

Rationale: The correct answer is C: Recruitment and activation of immune cells. C5a is a potent chemoattractant that attracts immune cells to the site of infection or inflammation. It also activates these immune cells, leading to enhanced immune responses. Option A (Opsonization) and B (Cell lysis) are not the main functions of C5a. Option D (Inhibition of inflammation) is incorrect because C5a actually promotes inflammation by recruiting and activating immune cells.