Answer:
Propagation of an Electromagnetic Wave. Electromagnetic waves are waves which can travel through the vacuum of outer space. Mechanical waves, unlike electromagnetic waves, require the presence of a material medium in order to transport their energy from one location to another.
Answer:
An object in a motion when it is continuously changing its position based on a reference point and observed by a person or a device.
D. Empty Space
Imagine an apple in the center of a football field. Pretend like that apple is the nucleus of an atom. The electrons would be at the end-zones. The universe is just a butttonne of empty space