Final answer:
The genetic difference between humans and chimpanzees is larger than 2% due to gradual genetic changes and differences that have occurred over millions of years of evolution from a common ancestor.
Step-by-step explanation:
The genetic difference between humans and chimpanzees is larger than 2% because the two species have evolved from a common ancestor over millions of years, leading to gradual genetic changes and differences. Although humans and chimpanzees share about 98% of their DNA, it's important to note that even a small percentage of genetic difference can result in significant morphological and physiological variations between species. This accounts for the differences in appearance, behavior, and brain size observed between humans and chimpanzees.