Layers - Variables

I think that problem is that you have put the "Show layer X" -trigger on the Layer X itself. Those need to be on the base layer.

What you have is done is basicly this: "Use there keys to open this locked door", but you have put the keys behind that locked door.

One other idea too:

There is no need for the additional layer to have every object of the base layer copied there. a layer can just have some objects in it, and rest can shown from the base layer "through" the additional layer. In this case the additional layers could just be those answer boxes, and everything else could be shown from the base layer.

In your case each additional layer contains new set of buttons that appear on top of base layer buttons, and you would need to then make a complete set of triggers for every layer in order for those buttons work in each layer. That just seems too much of needless work.