Final answer:
Transparency is the feature used to remove a single-color background.
Step-by-step explanation:
The feature used to remove a single-color background is Transparency. This feature allows you to make a specific color transparent, making it appear as if the background is removed.
By using transparency, you can blend images with different backgrounds seamlessly. For example, if you have a logo with a white background and you want to place it on a colored background, you can use transparency to remove the white background and have the logo appear without any background.