When the day of the competition finally arrived, Brittany was plagued with nerves. Her parents were in the stands, and Coach Jen was in the front row beside other coaches. Brittany practiced her moves and, although she had memorized the routine, she felt clumsy and insecure. Brittany stood with a solemn expression, concerned that this was about to be a disaster.
In the passage above, what does solemn mean?