Correct Answer: A

Rationale: The correct answer is A: TRUE. The innate immune system is the body's first line of defense against infections and is always active, providing immediate protection without prior exposure to a specific pathogen. It includes physical barriers, such as skin and mucous membranes, and cellular components like phagocytes and natural killer cells. The innate immune response is nonspecific and rapid, providing a crucial initial defense against pathogens. Choice B is incorrect because the innate immune system is always active, even without any prior exposure to pathogens. Choice C is incorrect because the innate immune system is consistently functioning to protect the body, regardless of the situation. Choice D is incorrect as the correct answer is A.

Correct Answer: B

Rationale: The correct answer is B: Clostridium botulinum. This bacterium is capable of forming spores as a survival mechanism in harsh conditions. Spore formation allows it to remain dormant until conditions become favorable for growth again. Staphylococcus aureus (A), Escherichia coli (C), and Neisseria gonorrhoeae (D) do not form spores and rely on other mechanisms for survival. Staphylococcus aureus is a common skin bacterium, Escherichia coli is a gut bacterium, and Neisseria gonorrhoeae is a sexually transmitted bacterium.

Correct Answer: C

Rationale: The correct answer is C: Corynebacterium diphtheriae. This bacterium causes diphtheria, a disease characterized by a pseudomembrane in the throat. This pseudomembrane is a result of the bacterial exotoxins causing inflammation and necrosis of the throat tissues. Clostridium tetani (A) causes tetanus, characterized by muscle stiffness, not a pseudomembrane in the throat. Bordetella pertussis (B) causes whooping cough, with symptoms of severe coughing fits but no pseudomembrane. Streptococcus pyogenes (D) causes strep throat, but does not produce a pseudomembrane.

Correct Answer: B

Rationale: The correct answer is B: Mycobacterium tuberculosis. Mycobacterium tuberculosis is the causative agent of tuberculosis, as it specifically infects the lungs and can spread to other parts of the body. Mycobacterium leprae (Choice A) causes leprosy, not tuberculosis. Bacillus anthracis (Choice C) causes anthrax, not tuberculosis. Staphylococcus aureus (Choice D) is a common bacterium known for causing skin infections, not tuberculosis. Therefore, Mycobacterium tuberculosis is the correct answer for the causative agent of tuberculosis.

Correct Answer: A

Rationale: The correct answer is A: Metronidazole. Metronidazole is a synthetic antiprotozoan drug with high activity against Helicobacter pylori, a bacterium that can cause wound infections. Metronidazole specifically targets anaerobic bacteria like H. pylori, making it effective in preventing wound infections. Incorrect choices: B: Doxycycline hydrochloride - Doxycycline is primarily used for bacterial infections, not protozoan infections like H. pylori. C: Chingamin - Chingamin is not a commonly used drug for treating H. pylori infections or preventing wound infections. D: Acyclovir - Acyclovir is an antiviral drug used to treat herpes infections, not bacterial or protozoan infections like H. pylori.