Why do scientists think that introns and exons contribute to evolutionary flexibility?

What is a codon and where is it found

Long-period comets come from the oort cloud particles in earth’s atmosphere material from the asteroid belt the kuiper belt

Migration is a. the movement of organisms from a native location to a foreign location b. the movement of organisms from a foreign location to a native location the movement of organisms from their water supply to their food supply d. the seasonal movement of organisms between locations c. select the best answer from above