Final answer:
Jessie and Kristin are monozygotic, or identical twins, because they developed from a single fertilized egg and possess identical genes.
Step-by-step explanation:
Jessie and Kristin are twins that developed from a single fertilized egg, making them monozygotic twins, which are also known as identical twins. Identical twins have all the same genes because they develop from the same fertilized egg and thus inherit copies of the same chromosomes. In contrast, fraternal twins or dizygotic twins develop from two different eggs that are fertilized by two different sperm, resulting in genetic variation similar to that found in siblings born at different times.