The lipophilization is:

Correct Answer: A

Rationale: The correct answer is A because lipophilization is the process of removing water from cells under deep vacuum in a frozen state. Dehydration of the cell at a low temperature helps to preserve the cellular structure and components. Choice B is incorrect as hydration does the opposite of what lipophilization aims to achieve. Choice C is incorrect as lipophilization does not involve enriching cells with proteins. Choice D is incorrect as lipophilization does not involve removing protein content from cells.

Correct Answer: C

Rationale: Step 1: Chlorhexidine belongs to the group of biguanides, which are commonly used for disinfecting hands, skin, and mucous membranes. Step 2: It is known to have broad-spectrum antimicrobial activity against various pathogens. Step 3: The usage of chlorhexidine in healthcare settings for preoperative skin preparation and surgical hand scrub is well-established. Step 4: The effectiveness and safety profile of chlorhexidine make it a preferred choice for disinfection purposes. Summary: - Option A is incorrect as chlorhexidine is not characterized by strong human toxicity. - Option B is incorrect as chlorhexidine is not classified as an alcohol and is primarily used for disinfecting hands, skin, and mucous membranes. - Option D is incorrect as chlorhexidine has a wide range of applications in disinfection, especially in healthcare settings.

Correct Answer: D

Rationale: The correct answer is D, as all options A, B, and C are determinants of antigenicity. A: Chemical nature influences how the immune system recognizes antigens. B: The size of the antigen affects its ability to be recognized by immune cells. C: Antigens of foreign origin are more likely to trigger an immune response. Therefore, all of these factors together play a crucial role in determining antigenicity.

Correct Answer: D

Rationale: The correct answer is D. Sepsis is a systemic response to infection resulting in organ dysfunction. A: Sepsis can be caused by bacterial infection, but it is not solely defined by the presence of bacteria in the blood. B: Bacteremia is the presence of bacteria in the blood, which can be a component of sepsis, but sepsis involves a broader systemic response beyond just bacteremia. C: Sepsis can lead to the release of toxins and organ failure, but sepsis itself is not defined solely by the massive proliferation of toxins. Therefore, the correct answer is D, as sepsis can involve the presence of bacteria, bacteremia, systemic manifestations, and organ failure.

Correct Answer: B

Rationale: The correct answer is B because lysozyme, lactoferrin, interferon, and complement are all humoral factors involved in natural resistance. Lysozyme and lactoferrin are antimicrobial proteins that help defend against pathogens. Interferon is a signaling protein that inhibits viral replication, while complement is a group of proteins that enhance the immune response by promoting inflammation and opsonization. Choices A, C, and D are incorrect: - Choice A mentions only macrophages, which are not humoral factors but rather phagocytic cells. - Choice C lists immune cells involved in adaptive immunity (B and T lymphocytes, NK cells) rather than humoral factors of natural resistance. - Choice D includes immunoglobulins, which are part of adaptive immunity, not natural resistance.