Final answer:
The term used to describe slow and graceful movements in ballet is Adagio.
Step-by-step explanation:
In ballet, the term used to describe slow and graceful movements that develop a sense of line, balance, control, and strength is Adagio. Adagio is an important component of ballet, allowing dancers to showcase their control, strength, and technique while maintaining a smooth and fluid movement. These movements require a great deal of control, as well as the ability to hold positions and transitions for an extended period of time.