Final answer:
Tarah is part of a crowd at a sold-out concert, which is a large gathering often studied in social psychology to understand group behavior and influences.
Step-by-step explanation:
Tarah is attending a sold-out concert at Red Rocks, with thousands of other fans of the artist. Tarah is part of a crowd. This term refers to a large number of people gathered together, typically in a disorganized or unruly way, often for a shared purpose like attending a concert, sporting event, or protest.
The dynamic of a crowd can be studied in social psychology which observes how individuals behave in groups and how being part of a crowd can influence individual behavior.