Final answer:
We can determine the approximate age of a child by examining the epiphyseal plates in an x-ray of their bones. These plates are made of cartilage and appear as dark epiphyseal gaps in the x-ray image. As the child grows older, the plates fuse and become solid bone.
Step-by-step explanation:
To determine the approximate age of a child, we can examine the epiphyseal plates in an x-ray of their bones. Epiphyseal plates are present in growing bones and are seen as dark epiphyseal gaps near the ends of long bones in the x-ray image. These plates are made of cartilage and appear less dense than the surrounding bone. As the child grows older, the epiphyseal plates fuse and become solid bone. By analyzing the presence or absence of epiphyseal plates, we can estimate the approximate age of the child.