Final answer:
An Arabesque is a basic ballet pose characterized by one leg being extended straight to the back. This pose is often depicted in ballet performances and artwork, such as those by Edgar Degas.
Step-by-step explanation:
The basic pose in ballet characterized by a straight leg extension to the back is known as an Arabesque. This position requires the dancer to balance on one leg while the other leg is extended straight behind them, generally at a 90-degree angle or higher, depending on the dancer's flexibility and strength.
Ballet, an art form celebrated by the works of Edgar Degas, emphasizes form, elegance, and the body's positions. His paintings such as The Ballet Class capture the essence of ballet by depicting dancers in various classical ballet poses, although they do not highlight the technical terms for each position. The arabesque is often seen in ballet performances and is considered one of the most visually striking and challenging poses.