Final answer:
The descriptive term for the texture in Bach's Wachet auf where the strings play one melody while the tenors sing another is polyphonic texture.
Step-by-step explanation:
The descriptive term for the texture in Bach's Wachet auf where the strings play one melody while the tenors sing another is polyphonic texture. In polyphonic texture, multiple melodic lines are heard simultaneously, creating a rich and complex musical texture. Each melodic line is independent and can be heard as an individual voice, just as the groups of instruments or singers are in this piece.