What is the purpose of a selvage on woven material?

The purpose of a selvage on woven material is to prevent unraveling. A selvage is the tightly woven edge of the fabric that ensures the threads do not come apart, maintaining the integrity of the material. This is particularly crucial in weaving because it helps to retain the shape of the fabric and avoids fraying, which can compromise both the appearance and durability of the fabric.

In contrast, while aesthetic appeal may be impacted by the design of the selvage, its primary function is structural rather than decorative. Increasing flexibility and adding weight are not roles that selvages fulfill; they do not influence the mechanical properties of the fabric in those ways. Therefore, the correct answer emphasizes the protective and functional role of the selvage in maintaining the woven fabric's quality.