Combining Layers and Working with them??

I am a new Photoshop CS user and I was wondering if there was a way to combine layers and still be able to move or adjust the separate objects on that layer.

Example: I have a layer with a circle object on it and a layer with a square object on it. Can I bring the circle on to the square layer and still adjust the properties of each object individually?

I apologize if this is a dumb question...I am new to this.

Why not just keep them as layers?

The only reason I was wondering is laziness...Just to move and edit without switching layers all the time.

To move multiple layers simultaneously, you can link them together

Or Group them