Radio waves are visible. Radio waves have a high frequency. Radio waves spread in all directions. Radio waves are created by the animal.
Collars that emit radio waves are sometimes placed on animals to find their location. Which is the best reason for using radio waves as a method of tracking the animals?

Options:
- Radio waves are visible.
- Radio waves have a high frequency.
- Radio waves spread in all directions.
- Radio waves are created by the animal.

Radio waves spread in all directions.