Complex sentence: Today we know that there are anatomical and physiological differences between pigs and humans, as with all species, however, the many similarities that do exist make pigs an incredibly valuable model for the study of both human and animal disease.
Split into simpler sentences: Today we know that there are anatomical and physiological differences between pigs and humans. As with all species, however, the many similarities that do exist make pigs an incredibly valuable model for the study of both human and animal disease.