You can reduce the number of layers in the page without deleting any objects, by merging layers. When you merge layers, objects from the merged layer are moved to the current layer.
1.On the Layers palette, double-click the layer you want to choose as merge target. The icon appears before the layer name.
2.Check-out the list of layers.
3.Click the layer you want to merge to the target (Note: it must be a different layer).
4.On the Layers palette, right-click the list, and then select Merge to current.
Note
You cannot merge a shared layer.