Answer:
Pincer grasp
Explanation:
The pincer grasp is coordination between index finger and thumb. When you hold your shirt button and closing and use your pen for writing, a person uses the coordination of index finger and thumb.
It is the second nature in adults but found most prominent in the development of children. It shows the best coordination between the brain and the muscles. It helps the child to grasp items. Every child develops it at different rates and different levels.
Thus when a baby's ability to expands things greatly by the development in Pincer grasp. It is the coordination between thumb and index finger.
