grace sent sms of 60 words, if she paid 40k for the first 12 words, 2k for each extra word. how much did she pay?

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.