Whenever we add a layer to our Motion projects, it has to be contained in a group. But what exactly is the difference between layers and groups? Well, for one thing, a layer is an element—a picture, movie, text object you've brought in or created. A group is a container for those elements. It can be used to organize materials in your project or perform operations to several elements at once. For those of you who use Final Cut Pro X, you may be familiar with compound clips. Compound clips allow you to reverse render operations or make universal changes to several objects at once. Let's take a brief look at some of the fundamental differences between groups and layers in this following exercise.