Correct Answer: B

Rationale: The correct answer is B: Facultative anaerobes. Facultative anaerobes can survive in both oxygen-rich and oxygen-poor environments by switching between aerobic and anaerobic metabolism. They have the flexibility to use oxygen if present but can also ferment in the absence of oxygen. Obligate anaerobes (
A) cannot survive in the presence of oxygen, obligate aerobes (
C) require oxygen for survival, and microaerophiles (
D) require low levels of oxygen for growth, unlike facultative anaerobes.

Correct Answer: B

Rationale:
Step 1: Mycobacterium tuberculosis is a bacterium known to cause tuberculosis.

Step 2: Mycobacterium leprae causes leprosy, not tuberculosis.

Step 3: Streptococcus pneumoniae causes pneumonia, not tuberculosis.

Step 4: Neisseria gonorrhoeae causes gonorrhea, not tuberculosis.
Conclusion: Mycobacterium tuberculosis is the correct answer as it is the only bacterium associated with tuberculosis among the choices provided.

Correct Answer: A

Rationale: The correct answer is A because most bacteria can grow in both the presence and absence of oxygen. Some bacteria are aerobic and require oxygen for growth, while others are anaerobic and can grow in the absence of oxygen.
Choice B is incorrect because not all bacteria grow in the absence of oxygen.
Choice C is incorrect because not all bacteria are microaerophiles, which are bacteria that require a low level of oxygen for growth.
Choice D is incorrect because most bacteria exhibit flexibility in their oxygen requirements.

Correct Answer: C

Rationale: The correct answer is C: circular double-stranded DNA. Bacterial genomes are typically composed of circular double-stranded DNA due to its stability and efficient replication. Circular DNA allows for continuous replication without the need for telomeres present in linear DNA (choice
B). Bacteria do not typically have double-stranded RNA genomes (choice
A) as RNA is more commonly found in viruses. Single-stranded DNA (choice
D) is not typically the main genetic material in bacteria, as it is less stable and less efficient for information storage compared to double-stranded DNA.

Correct Answer: B

Rationale: The correct answer is B: Acute purulent lymphadenitis. The symptoms described indicate an acute bacterial infection of the lymph nodes. The presence of painful lymph nodes, erythema, and shiny appearance of the skin overlying the nodes suggest an inflammatory process. The rise in temperature and frequent pulse indicate an active infection. The white-coated tongue may be a sign of systemic involvement. The shaky gait may indicate systemic toxicity. Bubonic plague (
A) presents with buboes, not just painful lymph nodes. Lymphogranulomatosis (
C) is a type of lymphoma and would not present with these acute bacterial infection symptoms. Anthrax (
D) typically presents with a black eschar and is less likely in this context.