The animals gnaw their food with incisors. They are very large in rodents, have no roots and grow all their lives. The incisors are constantly being ground and at the same time growing. They are covered with hard enamel only on the front. Therefore, the end of the incisor is erased not evenly, but obliquely: from behind it is stronger than from the front. This keeps the incisors sharp. Rodents do not have canines; they have a large free gap between the incisors and molars.
Predators have highly developed fangs, with which they kill prey. Large molars have a sharp-edged protrusion (predatory tooth), with which predators crush bones and gnaw through tendons. With razor-sharp incisors, they gnaw the bones of the murdered victim.
Remember: The process of learning a person lasts a lifetime. The value of the same knowledge for different people may be different, it is determined by their individual characteristics and needs. Therefore, knowledge is always needed at any age and position.