A lever has a total length of 12 meters with a fulcrum at the exact center of the lever. Which best describes how to double the mechanical advantage of the lever?

Move the fulcrum 2 meters away from the side on which the force is applied.

Explanation:

To double the mechanical advantage of the lever what we have to do is move the fulcrum of the lever away from the center and close to the side where the load is, by doing this, we are making the effort arm larger and multiplying the resistance that the lever can lift with the same effort.

the mantle

explanation:

earth is divided into three layers: the crust or the outermost layer on which we live; the underlying, middle layer - the mantle - and the core (the innermost layer of earth).