Christopher has trouble determining whether a song is a motet or a Mass. What is the BEST way for him to distinguish between these two types of music?

A Mass is a musical setting of texts from the Catholic liturgy, so it is religious. Motets are usually sacred, but motets can also use secular texts, making the subject matter a helpful distinction. The other choices are inaccurate: Mass settings are not always flexible, both forms can be polyphonic, and motets are not defined by being written in Greek.

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