In order to improve the condition of your muscular system, you could participate in aerobic activity at least
a.
3 minutes 5 times a week
b.
10 minutes 4 times a week
c.
30 minutes 3 times a week
d.
50 minutes 3 times a week
select the best answer from the choices provided.
a
b
c
d

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.