Some people prefer interval training because
a. the intensity of the exercise doesn't increase, only the time does. b. they can exercise at a steady, but slow, pace for longer periods of time. c. it's performed with speed and may not cause boredom. d. they've found that this type of training is best for beginners

Which of the following processes within viral replication is the greatest source of genetic variation in rna virus populations? a) high mutation rate due to lack of proofreading of rna genome replication errors.b) transcription from the host cell rna polymerase introduces numerous mutations.c) capsid proteins from the host cell can replace the viral capsid.d) viral rna is translated by host cell ribosomes.