What is the common characteristic of all waves?

All waves share the fundamental characteristic of transferring energy from one location to another without the physical transfer of matter. This energy transfer occurs through various mediums, depending on the type of wave. For instance, in mechanical waves, the medium (like air or water) oscillates to propagate energy, while in electromagnetic waves, energy travels through the vacuum of space.

The other options, although related to specific types of waves, do not apply universally. For example, not all waves travel in a straight line; they can bend, reflect, and diffract depending on the medium and other factors. Additionally, not all waves carry sound; sound waves are a specific type of mechanical wave, and many waves, such as light waves, do not produce sound. Lastly, while light waves can be seen, many waves such as sound or radio waves cannot be perceived by the human eye. Thus, the unique quality of energy transfer distinguishes all waves, making this option the correct one.