Correct Answer: D

Rationale: The correct answer is D because viruses have the ability to infect all organisms, including plants, bacteria, animals, and even fungi. Viruses are non-living entities that require a host cell to replicate and spread. They can infect a wide range of organisms by attaching to specific receptors on the host cell's surface. Therefore, the correct answer is D as viruses have the capability to infect all living organisms. Choices A, B, and C are incorrect because viruses can infect not only plants, bacteria, and animals but also other organisms, making choice D the most comprehensive and accurate option.

Correct Answer: A

Rationale: The correct answer is A because spheroplasts are bacteria with defective cell walls that have a parietal layer (peptidoglycan layer) and a defective peptidoglycan layer. This is because spheroplasts have lost their rigid cell wall structure, leading to an incomplete peptidoglycan layer. Choice B is incorrect as the cytoplasmic membrane is not directly affected by the loss of cell wall integrity. Choice C is incorrect because spheroplasts do not have an outer membrane defect, but rather a defect in the peptidoglycan layer. Choice D is incorrect because spheroplasts still have peptidoglycan, even though it is defective.

Correct Answer: A

Rationale: Step-by-step rationale: 1. Tularemia is caused by Francisella tularensis, a highly infectious bacterium. 2. Francisella tularensis is the only pathogen specifically known to cause tularemia. 3. The other choices (Bordetella pertussis, Brucella suis, Legionella sp.) are not associated with tularemia. 4. Therefore, the correct answer is A - Francisella tularensis.

Correct Answer: D

Rationale: The correct answer is D because all three viruses, Vaccinia virus, Smallpox virus, and Cowpox virus, belong to the genus Orthopoxvirus. They share similar characteristics and genetic makeup. Vaccinia virus is used as a vaccine against smallpox, Smallpox virus causes smallpox disease, and Cowpox virus can infect both animals and humans. Choice A, B, and C are incorrect because each of these viruses is a member of the Orthopoxvirus genus.

Correct Answer: C

Rationale: The correct answer is C: Thermophiles. Thermophiles are bacteria that thrive in high temperatures typically above 45°C. They have specialized enzymes and cellular structures that allow them to survive and even thrive in extreme heat. Psychrophiles (A) are adapted to cold temperatures, mesophiles (B) thrive at moderate temperatures, and halophiles (D) prefer high salt concentrations, making them unsuitable for extreme heat survival. Therefore, Thermophiles are the only bacteria among the choices that are known for their ability to survive in extreme heat.