A Classmate Argues That the Three Domains of Life Should

question 240

Multiple Choice

A classmate argues that the three domains of life should be four domains, with the fourth domain containing viruses.Which is not an appropriate response to this argument?

• A)Viruses are certainly derived from living cells, but because the different viruses evolved multiple times from different ancestors, they don't belong in a shared, single domain.
• B)The rapid mutation rate, which results in rapid evolution of virus genomes, tends to cloud evolutionary relationships over long periods.
• C)The tiny size of many virus genomes restricts the phylogenetic analyses that can be conducted to relate viruses to cellular organisms.
• D)Some biologists do not consider viruses living organisms, because they are not cellular but depend on cellular organisms for basic life functions such as metabolism and reproduction.
• E) Viruses often are inserted into a host's genome, making it impossible to distinguish between viral DNA and host genomic DNA.