Im not sure but here is some information to help A declarative question is a yes-no question that has the form of a declarative sentence but is spoken with rising intonation at the end. Declarative sentences are commonly used in informal speech to express surprise or ask for verification.
Sound energy is produced when an object vibrates. The sound vibrations cause waves of pressure that travel through a medium, such as air, water, wood or metal. Sound energy is a form of mechanical energy. (I believe this is it)
