Question: The rate of evolution is not uniform across the entire 18S rDNA gene. Within the 18S gene, there are regions that are very conserved (evolve very slowly) and regions that evolve more rapidly. The difference in evolutionary rate is most likely due to: Group of answer choices Exons in the 18S gene are present in the final product so mutations can have a negative effect on the function of the final product. Difference in the frequency with which mutations occur within the gene region. Introns in the 18S gene are remove from the final product so mutations generally have little or no effect on the function of the final product. Differences in the effects of mutations in different regions on the function of the rRNA product.