How did the crusades lead to the decline of feudalism?

What happened 10 million years ago? if u answer, u get 50 ! plz answer ; -;

What industry was exempt from the child-labor laws passed in the factory act of 1833?

Which points did chief justice roger b. taney use to justify the supreme court’s ruling in the dred scott case? the property clause of the constitution, the due process clause of the fifth amendment, and the fact that african americans were not citizens. the practice of judicial review established in marbury v. madison, the property clause of the constitution, and the due process clause of the fifth amendment. the necessary and proper clause of the constitution, the due process clause of the fifth amendment, and the fact that african americans were not citizens. the commerce clause of the constitution, the elastic clause of the sixth amendment, and the practice of judicial review established in gibbons v. ogden.