What causes fabric pilling in textiles?

Fabric pilling occurs when fuzzy fibers on the surface of textiles become loose due to wear and friction, particularly against other surfaces. These fibers then ball up and cling to the garment, forming small, unsightly tangles known as pills. This is particularly common in fabrics made from natural fibers like wool, or synthetic fibers that have a tendency to shed fibers during normal use.

Understanding the other options provides additional context about the phenomenon of pilling. While improper dyeing processes can lead to various issues with fabric quality, they do not directly relate to the mechanical action of fibers breaking and accumulating. Static electricity can contribute to fabrics attracting lint and dirt but is not a primary cause of pilling. Similarly, heat exposure during washing may affect fabric integrity, but the specific mechanism behind pilling is more about the physical properties of fibers rather than temperature during cleaning. Thus, the presence of fuzzy fibers that cluster together is the definitive cause of fabric pilling.