а. If yоu gо the Pennsylvаniа, yоu will find ridges that zig-zag back and forth with valleys between them. Why do the ridges zig-zag instead of being more or less straight like most fidge.b. If you go to Pennsylvania, will you find that the rocks on top of the ridges are older than those in the valleys, or it will be the other way around? Or, will there be places that are one way, and other places that are the other way? EXPLAIN YOUR ANSWER.