Answer:
The circumstances of the bears’ dance.
Explanation:
In this paragraph, the author questions “what music” the bears could be hearing “as they dance under the full moon.” The author characterizes the bears’ dance as a “brilliant silence” to refer to the conditions in which the dance occurs. The full moon (and its reflection from the walls of the crater) provides bright light for the bears to see by, and there is no external music, so the dance is silent.
