What drives the emergence of immuno-resistant pathogen strains?

Correct Answer: C

Rationale: The correct answer is C: Rapid pathogen reproduction and mutations drive the emergence of immuno-resistant pathogen strains. This is because the high rate of reproduction allows for more opportunities for mutations to occur, some of which may confer resistance to the host's immune system or medical interventions. Slow mutation rates in pathogens (B) would not lead to the rapid emergence of resistant strains. Host immune system failure (A) occurs after the pathogen has already developed resistance. The absence of host immune adaptation (D) does not directly drive the emergence of resistant strains as it is the rapid reproduction and mutations of pathogens that play a crucial role.

Correct Answer: B

Rationale: The correct answer is B: 1796. This is because the first vaccine for smallpox was developed by Edward Jenner in 1796. He used cowpox virus to create immunity against smallpox. Choices A, C, and D are incorrect because they do not align with historical records of the development of the smallpox vaccine. Choice A (1726) is too early, choices C (1882) and D (1895) are much later dates and do not correspond to the actual timeline of the smallpox vaccine's discovery.

Correct Answer: B

Rationale: The correct answer is B: Recognition, ingestion, and digestion. Firstly, recognition is essential for phagocytes to identify and bind to the target. Next, ingestion involves engulfing the target into a phagosome. Finally, digestion occurs within the phagolysosome, where enzymes break down the target. Choices A, C, and D are incorrect because they do not accurately represent the sequential key steps of phagocytosis.

Correct Answer: D

Rationale: The correct answer is D. Innate immunity does not involve producing antigen-specific antibodies. This is because innate immunity is the first line of defense against pathogens and does not have the ability to produce antibodies that target specific antigens. Instead, innate immunity works through mechanisms like phagocytosis and killing infected cells to eliminate pathogens. Choices A, B, and C are functions of innate immunity. A - Killing virally infected cells is a common function of innate immunity. B - Phagocytosis is the process by which immune cells engulf and destroy pathogens, a key function of innate immunity. C - Activating adaptive immunity is also a role of innate immunity, as it helps initiate the adaptive immune response for a more targeted defense.

Correct Answer: C

Rationale: Rationale: 1. Deficiencies in the classical pathway lead to impaired clearance of immune complexes, hence contributing to SLE. 2. This pathway plays a crucial role in removing self-antigens and maintaining immune tolerance. 3. Increased cancer risk (A) is not directly linked to classical pathway deficiencies. 4. Resistance to bacterial infections (B) is more associated with deficiencies in the alternative pathway. 5. Overactivation of adaptive immunity (D) is not a direct consequence of classical pathway deficiencies.