Final answer:
The caller is the person who instructs square dancers on which moves to perform, and they play a crucial role in guiding the dance.
Step-by-step explanation:
In square dancing, the dancers are guided through their moves by a person known as the caller. This individual announces the steps and sequences that the dancers should perform, helping to coordinate the movements of the dance in time with the music. The caller plays an essential role in ensuring that the square dance runs smoothly, directing the action from the start to the end of the dance.