Final answer:
The bass note in a second inversion E-flat major triad is G.
Step-by-step explanation:
In a second inversion E-flat major triad, the bass note is the fifth of the triad. The second inversion means that the fifth of the triad is in the bass position, meaning it is the lowest note. In the key of E-flat major, the triad consists of the notes E-flat, G, and B-flat. In second inversion, the bass note is G.