Describe how our skin darkens in the presence of sun. In your description, be sure to name the pigment that darkens our skin and describe how skin darkening protects our DNA from damage.

How many calories are in one pound of fat

Which example is a indication of stress a. becoming more alert b. narrowing air passages c. slowing down if the heartbeat d. decreasing blood sugar with adrenaline

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.