Answer:
Because eukaryotic genes contain introns
Step-by-step explanation:
Eukaryotic genes are much more complex than prokaryotic genes. Some of the differences between these two groups of organisms are:
- existence of exons and introns (which are spliced during the process of mRNA processing)
- post-transcriptional modifications (poly A tail and 5' cap)
- regulatory elements which control gene expression.
On the other hand, prokaryotic genes are organized in operons, structural units that contain more that one gene, under the control of one promotor.