Which property is unique to electromagnetic waves? (1 point) They can be controlled by the pull of gravity. They can shake structures on Earth. They can travel on the surface of water. They can travel in a vacuum.

## Step 1<br />The problem asks us to identify a property that is unique to electromagnetic waves. Electromagnetic waves are a type of wave that can travel through a vacuum, which means they do not require a medium to travel through. This is a unique property of electromagnetic waves.<br /><br />## Step 2<br />Let's analyze each option:<br /><br />1. "They can be controlled by the pull of gravity." - This is not unique to electromagnetic waves. All objects with mass, including electromagnetic waves, are subject to gravity.<br /><br />2. "They can shake structures on Earth." - This is not unique to electromagnetic waves. Seismic waves, for example, can cause structures on Earth to shake.<br /><br />3. "They can travel on the surface of water." - This is not unique to electromagnetic waves. Surface waves, such as those that travel across a lake or ocean, can travel on the surface of water.<br /><br />4. "They can travel in a vacuum." - This is unique to electromagnetic waves. Unlike mechanical waves, electromagnetic waves do not require a medium to travel through and can travel through a vacuum.