Final answer:
During the 1970s, French hairdressers introduced the art of hair weaving using yarn as a versatile and colorful option for adding decorative patterns and highlights to hairstyles.
Step-by-step explanation:
The art of hair weaving using yarn was introduced by French hairdressers during the 1970s. This technique involved weaving strands of yarn into the hair to create decorative patterns and highlights. Yarn provided a versatile and colorful option for adding texture and visual interest to hairstyles. Other materials like ribbons, foils, and beads were also used for hair weaving, but yarn was a popular choice due to its flexibility and availability.