The lower jaw in mammals made up of dantary ( mendible) and some small postdentary jaw bones.....

The lower jaw in mammals is made up of the dentary bone.

The lower jaw, also known as the mandible, is an important component of the skull in mammals. It is the bone that forms the lower part of the jaw and holds the teeth. In most mammals, the lower jaw is comprised of a single bone called the dentary bone.

Explanation:

1. Structure of the Lower Jaw:
The lower jaw in mammals is a paired structure, consisting of a left and right side. Each side of the lower jaw is made up of several bones, including the dentary bone, which is the largest and most important bone.

2. Dentary Bone:
The dentary bone forms the main body of the lower jaw and holds the teeth. It is a large, robust bone that is located on the sides of the lower jaw. In mammals, including humans, the dentary bone is the only bone in the lower jaw that directly articulates with the skull. It is attached to the skull by the temporomandibular joint, allowing for movements of the jaw during chewing and speaking.

3. Other Bones in the Lower Jaw:
While the dentary bone is the main bone of the lower jaw, there are other smaller bones that contribute to its structure. These include the angular bone, which forms the posterior part of the lower jaw, and the splenial bone, which lies on the inner side of the dentary bone. However, these bones are not as prominent as the dentary bone and do not play a significant role in the overall function of the lower jaw.

4. Function of the Lower Jaw:
The lower jaw plays a crucial role in various functions, including biting, chewing, and speech production. It provides support for the teeth and helps in the process of mastication, which is the mechanical breakdown of food. The lower jaw also plays a role in the production of speech sounds by providing a movable platform for the tongue and other articulatory structures.

Conclusion:
The lower jaw in mammals is primarily made up of the dentary bone. This bone forms the main body of the lower jaw and is responsible for holding the teeth and allowing for movements of the jaw. While there are other smaller bones in the lower jaw, such as the angular and splenial bones, the dentary bone is the largest and most important bone in this region.