Using groups, nested groups, and Isolation Mode for improved workflow
Any time you create an item consisting of several objects, those objects can then be selected and combined into one group. In Figure 10.12, you can see that I have selected both the green treetop shape and the brown tree trunk shape (hold Shift while clicking on each):
After selecting the objects you would like to be combined, navigate to Object > Group (Ctrl/Command + G) in the top menu. This will create a connected relationship between these shapes that makes it easy to perform further adjustments to them. Adjustments such as sizing and position can now be performed as though these objects are a single unit. When needed, the object can also be ungrouped to adjust individual components.
After creating a group, it will appear in the Layers panel as one item labeled <Group>. Just to the left of this label will be a small arrow...