Why is important to brush your teeth twice a day? So visits to the dentist will be less painful? To keep your teeth shiny and white? To keep them healthy and strong?
These are all good reasons! But if you were a limpet, you wouldn’t worry about brushing your teeth, even though your teeth would be made of the strongest stuff in the world and worthy of good dental care. If you were a limpet, you wouldn’t have hands to hold your toothbrush, because you’d be a mollusk.