How do scientists know that fossils came from dinosaurs? How can they tell? What other evidence might they look for? Please answer me now don't stay long please

We dare not forget today that we are the heirs of that first revolution. let the word go forth from this time and place, to friends and foe alike, that the torch has been passed to a new generation of americans-born in this century, tempered by war, disciplined by hard and bitter peace, proud of our ancient heritage-and unwilling to witness or permit the slow undoing of those human rights to which we are committed today at home and around the world. let every nation know, whether it wishes us well or ill, that we shall pay any price, bear by burden, meet any hardship, support any friend, oppose any foe, in order to assure the survival and the success of liberty.