To produce sound, an object must be .

Any object that vibrates will create a sound. The sound could be musical or it could be noisy; but regardless of its quality, the sound wave is created by a vibrating object. Nearly all objects, when hit or struck or plucked or strummed or somehow disturbed, will vibrate.

rosevelt. 1973. "slaves everywhere"

b) the confederacy had to pay all union war expenses.