What indicates that an individual is younger based on their pubic and rib bones?

The correct answer highlights that specific features of bones can help determine an individual's age. In the context of the pubic and rib bones, the characteristic of smooth edges typically indicates a younger individual. As people age, their bones undergo various changes, including the development of more rugged and worn surfaces with age-related wear and tear.

In younger individuals, the bones are generally more robust and less affected by the degenerative processes that contribute to roughness, such as the accumulation of wear from use or resorption of bone tissue. Specifically, the smooth edges of the bones suggest that they have not experienced the significant wear that may occur over time.

While features like a heavily contoured face may relate to age, they are less reliable than the condition of the bones themselves in forensic assessments. The porous and pitted surfaces or flat surfaces are more commonly associated with older individuals or different conditions of bone health and morphology. Thus, the smooth edges serve as a consistent indicator of youth when examining skeletal remains.