Steven puts the two stones in a rock tumbler. the tumbler spins so the rocks bump against each other. when the rocks are removed , he discovers that pebble one experienced more change than pebble two . what can steven best conclude about the stones ?

F. Stone 1 is softer and experienced a greater physical reaction.

Physical reaction is when an object's appearance changes, not the identity (which would be chemical reaction). Because stone 1 is softer, it would be easier to change its physical property. Since stone 2 is harder, it's more durable and therefore harder to change. 

I’m pretty sure the answer is D I might be wrong though