What is a characteristic of polyphony?

Polyphony is characterized by the presence of multiple independent melodies that can be sung or played at the same time, each maintaining its identity and importance within the musical texture. This distinct feature allows each melody to stand alone as a meaningful musical line, contributing to the overall richness and complexity of the sound. In a polyphonic texture, the interplay between these independent melodies creates a harmonious tapestry of sound, which is a fundamental aspect of compositions from the Renaissance and Baroque periods, for example.

The other options present different musical concepts that do not align with the definition of polyphony. A single melody with variations in tempo does not involve multiple independent lines, while a melody accompanied by a single chord suggests a more homophonic texture, which focuses on a primary melody supported by chords. Additionally, melodies that remain unvaried do not reflect the independence and complexity that are hallmarks of polyphonic structures.