Relation between work and thinking

How does the fitt principle apply to the development of successful personal fitness programs

The load is the pivot point of a lever.

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.