The earliest (geologically speaking) ceratopsid fossils are found in , but the last, from the end of the Cretaceous are only found in.

then that particular organisms become extinct.

if the type of the food available changes, then the frequency of beak types will change, because birds with beaks more suited to the available food will be more successful over time.

the missing space is phylum

b) the inside picture would look at a very high temperature in a very low ph