Correct Answer: A

Rationale: The correct answer is A: Bacillus anthracis. This bacterium is known to form highly resistant spores that can survive for long periods in soil. Bacillus anthracis causes anthrax, a dangerous disease that can be transmitted to humans and animals. The other choices, Francisella tularensis, Brucella abortus, and Yersinia pestis, do not form spores as resistant as Bacillus anthracis. Therefore, only Bacillus anthracis is likely to have survived in the soil of the old burial ground for animal refuse for over 50 years.

Correct Answer: A

Rationale: The correct answer is A: Anaerobic. Pulpitis is an inflammatory condition of the dental pulp, often caused by bacterial infection. Anaerobic bacteria are commonly associated with dental infections, making it likely to find them in the inoculated culture medium. Anaerobic bacteria thrive in the absence of oxygen, which is typical of the dental environment. Acid-resistant (B) and acidophilic (C) microorganisms are not specifically linked to pulpitis. Haemolytic (D) microorganisms typically lyse red blood cells, which is not a characteristic feature of bacteria causing pulpitis. Therefore, the most likely microorganisms to be found in the culture medium would be anaerobic bacteria.

Correct Answer: D

Rationale: The correct answer is D because the rubella virus has icosahedral symmetry, meaning it has a spherical shape with 20 equilateral triangular faces. This symmetry is common in many viruses and allows for efficient packaging of genetic material. Choice A is incorrect because the rubella virus does have glycoprotein spikes on its surface. These spikes help the virus attach to host cells. Choice B is incorrect because the rubella virus does have an envelope derived from the host cell membrane. This envelope plays a role in viral entry into host cells. Choice C is incorrect because the rubella virus is an ssRNA virus, not ssDNA. Its genetic material is single-stranded RNA, not DNA. In summary, the rubella virus has icosahedral symmetry and possesses glycoprotein spikes, an envelope, and ssRNA genetic material, making choices A, B, and C incorrect.

Correct Answer: A

Rationale: The correct answer is A: Antitoxic passive immunity. Antibotulinic serum contains pre-formed antibodies against the botulinum toxin, providing immediate protection to the patient. This is passive immunity as the patient does not produce their antibodies but receives them externally. Choice B is incorrect as botulism is not an infection, so the patient does not develop infection immunity. Choice C is incorrect because active immunity involves the body producing its antibodies after exposure to an antigen, which is not the case here. Choice D is incorrect as antimicrobic immunity relates to protection against microbes, not toxins like in botulism.

Correct Answer: C

Rationale: The correct answer is C: phialospores. Phialospores are conidiospores that bud off from a vase-shaped spore-bearing cell called a phialide. This structure is characteristic of fungi in the genus Penicillium. Arthrospores (A) are formed by the fragmentation of hyphae, porospores (B) are not a recognized term in mycology, and blastospores (D) are produced by budding from yeast cells. Therefore, C is the correct choice based on the specific description provided in the question.