Q. A recent study of the mouse-ear plant Arabidopsis thaliana found that 44.9% of the DNA nucleotides within genes are either C or G (cytosine or guanine), but those same two bases represent only 37.6% of the nucleotides in the regions between genes. Clearly explain why chromosomal regions that do not code for proteins might experience natural selection for reducing the number of C and G nucleotides. Then propose a specific, testable evolutionary hypothesis for why regions that do code for proteins might have a greater number of C and G nucleotides. I don't really understand what my teacher wants me to say here. This is for my freshman biology class. It's strange because I've taken Bio before in high school, but this seems a bit awkward to me. Any help would be greatly appreciated. I'm gonna try and work this one out as well as a few others.