Final answer:
The asymmetry in cinder cones, such as Menan Buttes, is caused by the force of the explosion during the eruption.
Step-by-step explanation:
The asymmetry in cinder cones, such as Menan Buttes, is caused by the force of the explosion during the eruption. When a cinder cone erupts, the rim of the crater is turned up by the force of the explosion, causing it to rise above both the floor and the surrounding terrain. This creates an asymmetric shape, with one side of the cone being higher than the other. Additionally, the ejecta blanket surrounding the rim falls back to create a rough, hilly region, contributing to the asymmetry.