So there are five toy car parts that together make up the toy. I already wondered about how you create a whole model made out of individual parts and that you can work with each one as an individual object or combined group of objects. Here it's like that but I also thought it will be visualized in the Outliner Editor the same way. But here we have 'truck base' part consisting of other truck parts and when selected it shows... well it shows what object name suggests but not what by my hierarchy understanding it suppose to (which is whole truck selected).
P.S. How the front and the back wheels are connected? When I apply material to one object it automatically applies to the other.
Hey Lera, good question! The reason the other parts move with the base, even when not selected, is because of parenting (making one object inherit the transformations of another object). You'll learn all about that in this course: https://cgcookie.com/course/fundamentals-of-rigging
The wheels are connected in a different way. They are two separate objects but they share the same mesh data, which is what materials are assigned to. You can learn more about mesh data and material linking here: https://cgcookie.com/course/understanding-blender-data
Hope that helps!