1. Which of the following is a characteristic feature of the Orthomyxoviridae family of viruses? A) Single-stranded RNA, positive polarity B) Double-stranded RNA C) Single-stranded RNA, negative polarity D) Double-stranded DNA Answer: C) Single-stranded RNA, negative polarity Rationale: The Orthomyxoviridae family, which includes the influenza virus, is characterized by single-stranded RNA with negative polarity, allowing them to be transcribed directly into functional mRNA in the host cell. 2. The presence of envelope spikes is most associated with which viral function? A) Nucleic acid replication B) Protein synthesis C) Cell attachment and entry D) Virion assembly Answer: C) Cell attachment and entry Rationale: Envelope spikes contain proteins that bind to receptors on the host cell, facilitating viral entry into the cell. 3. A virus with helical symmetry is best described as: A) Spherical in shape B) Rod-shaped C) Complex and asymmetric D) Icosahedral Answer: B) Rod-shaped Rationale: Viruses with helical symmetry have a rod-shaped structure formed by the arrangement of protein subunits around the nucleic acid in a spiral fashion. 4. Which viral component is primarily responsible for the pathogenicity of the virus? A) Capsid B) Envelope C) Genome D) Surface proteins