Where are you people getting these ill posed questions? What level? Transitional forms! At the species level this would be explained as a rapid (geologically rapid) speciation event followed by years...
This question makes no sense, because there are plenty of transitonal fossils. So I'm just going to list some. Cladoselache tristychius ctenacanthus paleospinax spathobatis Protospinax Acanthodians...
the fossils show massive change at one time (for instance the Grand Canyon; this massive change occurs usually from significant weather/environmental events) , and during the periods between the...