One of the key ingredients of evolution by natural selection is variation. Within a population, evolution by natural selection will occur if there is a selective advantage of one variation over another. What are the sources of variation in living populations? Select all that apply. A. mutations in somatic cells B. environmental factors that may mutate DNA in gametes C. random mutations to DNA when DNA replicates in reproductive cells
D. Crossing over during meiosis

Predict the results of a two base insertion or deletion in a strand of dna that codes for a protien, how does this differ from a three base insertion or deletion?

In general, are there any major differences that you can see? explain

Define the apical impulse and describe its normal location, size, and duration. which abnormal conditions may affect the location of the apical impulse? explain the mechanism producing normal first and second heart sounds. describe the effect of respiration on the heart sounds. describe the characteristics of the first heart sound and its intensity at the apex of the heart and at the base. describe the characteristics of the second heart sound and its intensity at the apex of the heart and at the base.