48. RNA viruses accumulate nucleotide substitutions at rates several orders of magnitude higher than most DNA viruses. Experimental measurements show that the RNA-dependent RNA polymerase of many RNA viruses lacks 3’→5’ exonuclease proofreading activity, whereas DNA polymerases typically possess such activity. Which description directly represents the elevated evolutionary rates observed in RNA viruses?
(A) RNA viruses encode more genes involved in host interaction.
(B) RNA viruses are universally subject to stronger positive selection.
(C) RNA viruses consistently infect larger host populations.
(D) The absence of proofreading during genome replication increases mutation rates.
(E) RNA genomes are more likely to integrate into host chromosomes.