Question

the model shows the bird flu and human influenza infecting an intermediate host to produce a new influenza strain. what process is involved in producing an influenza strain with a new phenotype? a related viruses can recombine in a common host to express proteins with greater virulence. b influenza viruses incorporate host cell dna into their capsid to express host cell proteins. c viruses that infect intermediate hosts have higher rates of mutations, which produces new phenotypes. d the new viral strain incorporated rna molecules from the bird flu and proteins from the human influenza virus to create new dna molecules.

Explanation:

To determine the correct answer, we analyze each option:

• Option A: When related viruses (bird flu and human influenza) infect a common intermediate host, they can recombine their genetic material. This recombination can lead to the expression of new proteins (and thus a new phenotype) with potentially greater virulence, which matches the model of producing a new influenza strain.
• Option B: Influenza viruses are RNA viruses and do not incorporate host cell DNA into their capsid to express host cell proteins. Their replication involves RNA - related processes, so this option is incorrect.
• Option C: The model shows a recombination event between two different viruses, not a higher mutation rate in viruses infecting intermediate hosts. So this option does not explain the production of the new strain in the given model.
• Option D: Influenza viruses are RNA - based, and the process of creating a new strain here is recombination of viral RNA, not incorporating RNA from one virus and proteins from another to create new DNA molecules (influenza is an RNA virus, not a DNA - creating one in this context).

Answer:

A. Related viruses can recombine in a common host to express proteins with greater virulence.