Fill in the blank: An average healthy adult has about two ___ of blood, and it takes approximately 60 ___
for the cycle to be completed.

Why do rna viruses appear to have higher rates of mutation? a) rna nucleotides are more unstable than dna nucleotides. b) replication of their genomes does not involve proofreading. c) rna viruses can incorporate a variety of nonstandard bases. d) rna viruses are more sensitive to mutagens.