Gnawing teeth occur in A. Rodentia B. Lagomorpha C. Both A and B D. Pholidota
Hint: Gnawing refers to the action of biting or chewing something repeatedly, and wearing away bit by bit. Gnawing teeth is especially used to gnaw on hard foods.
Complete Answer: Gnawing teeth are mostly incisors, and they are present in animals. Incisors are the four front teeth which are present in both upper and lower jaw, which are primarily used for chewing and biting food. In rodents, their teeth do not have roots, or are called open rooted dentition, therefore, their teeth continue to grow. Of the sixteen teeth they possess, four of them are incisors.
So now let us analyze each of the options given to us and get into the correct option; Option A: Rodentia- The scientific order Rodentia mainly consists of rats, whose incisors are curved which helps in gnawing. Gnawing keeps their incisors sharp, so that they can chew easily on their food. Therefore, this is the correct option.
Option B: Lagomorpha- It is an order which consists of herbivorous mammals, which feed on their food by gnawing, and has rodents like incisors. Therefore, this is the correct option.
Thus, the correct option is C) Both A and B.
Note: A major difference between the Rodentia and Lagomorpha is that, the lagomorpha contains four incisors in the upper jaw itself, while Rodentia has a total four incisors only.