Terrain Handling For Performance Improvement in 2D Game

I am creating side scrolling skater game.

Basically I have loaded sequence of terrain and obstacle as per level design. But this causes performance issue in low end devices and I don't want to side out those devices.

I am basically a guy of AndEngine and new to Unity game development. In AndEngine, I have methods available for terrain rendering activation/deactivation for sprite as well as rigid body component.

So there is no performance overhead generated. But in Unity, at present I don't have any way to handle this problem.

If you want any more detail then I am always available so please help me in this.