Backbone.  That would be the BMW i3's carbon fiber.

"The BMW i3 is the first mass-production vehicle made with Carbon Fiber Reinforced Plastic (CFRP), a revolutionary material half the weight of steel and just as strong."

Reduce. The sustainability pitch...again.

"Four onsite wind turbines power the BMW i3 factory in Leipzig, Germany, and the carbon fiber in its frame is made in a hydroelectric-powered plant in Moses Lake, Washington."