Final answer:
Theme 1 in the 1st movement of 'Eine kleine Nachtmusik' has a homophonic texture, where a melody line is supported by chordal harmony.
Step-by-step explanation:
The texture of theme 1 in the 1st movement of Eine kleine Nachtmusik by Wolfgang Amadeus Mozart is homophonic. This piece is characterized by a melody line that is accompanied by chords. The melody is typically played by the first violins, while the accompanying chords are played by the second violins, violas, cello, and double bass.
In homophonic texture, the emphasis is on the melody, which is supported by harmonic accompaniment, creating music where one voice (melody) stands out prominently and the others form a background of harmonic support.