DINTII - ENGLEZA REFERAT SCOALA

Humans use teeth to tear, grind, and chew food in the first step of digestion, enabling enzymes and lubricants released in the mouth to further break down food. Teeth also play a role in human speech—the teeth, lips, and tongue are used to form words by controlling airflow through the mouth. Additionally, teeth provide structural support to muscles in the face and form the human smile. Like humans, most animals use their teeth to chew food, although many animals have evolved teeth that perform other specialized tasks. For example, many carnivorous (meat-eating) animals, such as tigers, have developed long, sharp teeth for clamping down on and killing prey. Beavers have chisel-like front teeth that they use to cut down large trees for building dams.