Answer:
1. Opposable thumbs are one of the characteristics of the primates that enhances their fitness. The thickest digit found in the hand is the thumbs that possess the tendency to rotate and move in distinct orientations in comparison to other digits. This makes the primates possess the tendency to hold the objects with the help of their hands in comparison to other animals that can only hold objects like food with the help of their mouth.
2. In case, if a primate infant fails to possess opposable thumbs, then it would become much tougher for him or her to pick the objects. With practice and time, the individuals would develop the habit of holding things with the help of other digits of the hand, however, the grasping power will not be that much or it can be said that such individuals would fail to exhibit strong grasping power.