Which of the following supports the idea that light is a wave

Which statement about sound is not true? a. air particles travel with sound waves. b. sound waves cannot travel through a vacuum. c. sound waves exist even if no one hears them. d. air particles vibrate along the path of a sound wave.

2. how is heavy water different from normal water

Needthe meter is the standard unit for: 1) height 2) length 3) weight 4) mass