What does the double bass in the classical orchestra do as in Mozart's eine kleine nachtmusik do?

In Mozart's "Eine kleine Nachtmusik," the double bass plays a crucial role in providing the harmonic foundation and rhythmic drive of the ensemble. It typically outlines the bassline, supporting the harmonic structure established by the violins and other string instruments. The double bass also adds depth and richness to the overall sound, enhancing the piece's lively and energetic character. Its presence helps to balance the texture, ensuring a fuller orchestral sound.