An orchestra is defined as a large instrumental ensemble typical of classical music. An orchestra features bass, brass, strings, woodwinds, and percussions. In the list given above, the section that is not one of the four groups in the orchestral palette is the voices. The answer would be "voices".
Explanation:
Cast and drop shadows are another common way to add depth. Reflections work similarly in that a reflection appears on a different surface. The illusion of depth can be increased by making the shadow larger and lighter and further away from the object. Blurring the edges of shadows also increases the illusion of depth.
