Problem:
Question 1: What are introns and exons?
Question 2: What do exons often correspond to?
Question 3: How do introns/exons compare in size in mammals? How does the occurrence of introns differ in lower eukaryotes vs. higher eukaryotes (e.g. fungi vs. mammals)?
Question 4: What is a possible evolutionary advantage of having an introns/exons organization to an organism's genes? Give an example of where this usage is observed or may have occurred.
Include source of information for best answer.