Feivel,
If dinos and manmmoths ect. did exist they lived and died before humans and eachother: tyronosaurus remains are never found with fossils of earlier dinos dinos are never found with mamoth or sabertooth tiger’s remains and these are never found with the bones or remains of humans or modern animals just from these layers alone you could prove that the world is more then six thousand years old ,now we also know the speed of light for a fact and there is nothing to indicate anywere that it has changed.