Which instrument is often used in orchestras and has a prominent melody section with resonating bars?

The xylophone is an instrument commonly found in orchestras that features a set of wooden bars arranged in a keyboard format. These bars are struck with mallets to produce musical notes, and they create a bright, resonant sound that allows for the performance of prominent melodic lines. The arrangement of the bars is such that each corresponds to a specific pitch, similar to a piano, but the xylophone's timbre is distinct due to the material of the bars, which enhances resonance. This characteristic makes it an effective instrument for carrying melodies, particularly in orchestral compositions, where it can stand out as a solo voice or contribute to the overall texture of the piece.

In contrast, while the piano, cello, and harp can all produce melodies, they do not feature the specific arrangement of resonating bars that defines the xylophone's sound and function in an orchestral setting.