Correct Answer: D

Rationale: The correct answer is D: Single stranded segmented (-) RNA. Orthomyxoviridae family includes influenza viruses, which have a genome composed of single-stranded segmented negative-sense RNA. This specific structure allows for efficient replication and transcription within host cells. Choice A is incorrect as orthomyxoviruses do not have a double-stranded DNA genome. Choice B is incorrect because orthomyxoviruses have a negative-sense RNA genome, not a positive-sense RNA genome. Choice C is incorrect as orthomyxoviruses do not have a double-stranded RNA genome.

Correct Answer: C

Rationale: The correct answer is C: All microorganisms. Sterilization aims to eliminate all microorganisms, including pathogenic and non-pathogenic ones, to ensure complete absence of viable organisms. This is crucial in medical, laboratory, and food preparation settings to prevent contamination and spread of infections. Choices A and B are incorrect because sterilization does not differentiate between pathogenic and non-pathogenic microorganisms, aiming to eradicate all. Choice D is incorrect as sterilization does involve releasing subjects (microorganisms) using physical methods.

Correct Answer: D

Rationale: The correct answer is D because all three bacteria listed produce toxins that cause damage to host tissues. Clostridium tetani produces tetanospasmin toxin causing tetanus, Vibrio cholerae produces cholera toxin leading to severe diarrhea, and Staphylococcus aureus releases toxins causing tissue damage in various infections. Therefore, all of the above choices are correct in terms of producing toxins that harm host tissues.

Correct Answer: C

Rationale: Step 1: The nucleocapsid is the structure containing the viral genome and the protein capsid. Step 2: The genome carries the genetic material of the virus. Step 3: The capsid is the protein coat that encloses and protects the viral genome. Step 4: Therefore, the correct answer is C: Genome and capsid. Summary: A: Capsid and spikes - Incorrect, spikes are not part of the nucleocapsid. B: Genome and envelop - Incorrect, the envelop is not part of the nucleocapsid. D: Capsid and envelope - Incorrect, the envelope is not part of the nucleocapsid.

Correct Answer: A

Rationale: The correct answer is A: Nystatin. Nystatin is an antifungal medication, not an antibiotic used to treat bacterial infections like generalized meningococcal infection. Penicillin G, macrolides, and chloramphenicol are antibiotics commonly used to treat bacterial infections, including meningococcal infections. Penicillin G is the drug of choice for meningococcal infections, while macrolides and chloramphenicol are alternative options. Nystatin is not effective against bacteria, so it is not a suitable treatment for meningococcal infections.