Is the rate your heart should beat at during exercise to be sure you are working hard enough to see a benefit
but not working too hard to be unsafe.

Ways to when your friend is going through social isolation?

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.

How do people attempt to explain the behaviors of others?