In parts of the united states midwest, you can find fossils of ancient sea creatures. some of these fossils could easily be mistaken for the remains of current day sea creatures, although they are only very distantly related. the ancient fossils are a record of when shallow seas covered much of the united states. while the fossils are of organisms that are the precursors of many modern day organisms, changes in ocean geography and other factors eventually caused those older species to become a) adapted b) evolved c) extinct d) obsolete