Tularemia is most often a:

Correct Answer: B

Rationale: The correct answer is B: Zoonosis. Tularemia is primarily a zoonotic disease, meaning it is transmitted from animals to humans. The bacterium that causes tularemia, Francisella tularensis, commonly infects animals like rabbits, rodents, and ticks, which serve as reservoir hosts. Humans can get infected through direct contact with infected animals, insect bites, or contaminated water or soil. This zoonotic nature of tularemia distinguishes it from anthroponosis (A), which is transmitted only between humans, and sapronosis (C), which is transmitted through non-living environmental sources. Choice D is incorrect because there is a correct answer, which is zoonosis.

Correct Answer: A

Rationale: The correct answer is A: 1 chromosome. Bacterial cells typically have a singular circular chromosome that contains their genetic material. This chromosome is essential for the cell's survival and contains all the necessary genetic information for its functions. Choices B, C, and D are incorrect because they refer to the chromosome numbers found in human cells (23 pairs or 46 individual chromosomes). Bacteria, being prokaryotic organisms, have a simpler genetic makeup compared to eukaryotic organisms like humans, hence they possess only one chromosome.

Correct Answer: B

Rationale: The correct answer is B: FALSE. The statement is incorrect because the secondary immune response is actually faster than the primary immune response. This is due to memory cells that are formed during the primary response, allowing for a quicker and more robust reaction upon re-exposure to the same antigen. The secondary response produces more antibodies and is more effective in clearing the pathogen. Choice A is incorrect because the secondary response is faster, not slower. Choice C is incorrect because the statement is objectively false, regardless of the situation. Choice D is incorrect as the correct answer is B.

Correct Answer: C

Rationale: The correct answer is C: Bacillus, Clostridium. Both Bacillus and Clostridium are known to form spores. Bacillus species produce endospores, which are resistant structures for survival in harsh conditions, while Clostridium species also form spores for protection and dispersal. The other choices are incorrect because Borrelia and Treponema are spirochetes and do not form spores, Bacteroides and Fusobacterium are anaerobic bacteria that do not produce spores, and Bordetella and Brucella are non-spore forming bacteria as well.

Correct Answer: B

Rationale: The correct answer is B: Diarrhea. Brucellosis typically presents with symptoms such as arthralgia, headache, and undulating fever, but diarrhea is not a common symptom associated with the disease. Brucellosis is primarily characterized by systemic symptoms like fever, joint pain, and headache due to the bacterial infection. Diarrhea is more commonly seen in gastrointestinal infections rather than brucellosis. Therefore, the absence of diarrhea as a symptom in brucellosis helps in differentiating it from other diseases with similar clinical presentations.