Answer:
The correct answer is: trilobite.
Step-by-step explanation:
Trilobites were the most common form of early sea life found in Oklahoma. Trilobites were arthropods that are now extinct. This marine species is thought to have lived during the early Cambrian period and they existed for almost 300 million years, before disappearing at the end of the Permian in the Permian-Triassic extinction event.
Dolomite is a sedimentary carbonate rock that is rich in calcium.
Bryozoans are a species of seaweed-like aquatic invertebrate animals that have lived since the early Ordovician period.
The Apatosaurus was a herbivore dinosaur that lived in North America during the Jurassic period. They had very long necks and were related to the Brontosaurus.