Final answer:
Mammals have specialized facial muscles and soft lips to help with feeding and communication, including the orbicularis oris and buccinator muscles, which facilitate chewing and speaking, and the red, sensitive lips are connected to pleasure centers in the brain.
Step-by-step explanation:
Mammals have specialized facial muscles and soft lips to assist with complex movements necessary for feeding and communication. The lips, with a thin layer of keratin and rich vascularization, are red and highly sensitive, connected to the cerebral cortex, which is likely why humans have a fascination with kissing. Under the skin of the lips is the orbicularis oris muscle, which controls the movement of material into and out of the mouth. The buccinator muscles in the cheeks help retain food while chewing, aiding in the mechanical breakdown of food for faster digestion and speaking. The presence of specialized muscles like the buccinator and complex dental structures also support the unique mammalian behavior of chewing, allowing for simultaneous breathing through a secondary palate that separates the nasal and oral cavities.