[A] classified [B] conclusion [C] discovered [D] exactly [E] existing

[F] immediately [G] inferior [H] massive [I] misidentified [J] prior

[K] question [L] remains [M] species [N] specimens [O] spot

The megalodon may have been a giant predatory sea creature measuring as much as 50 feet, but scientists believe it was no match for the competition posed by the great white shark—who they think wiped it out.

An international team of paleontologists (古生物学家) arrived at this【C1】_____as they tried to answer when the Otodus megalodon went extinct. They think the biggest ever shark was likely killed off at least a million years 【C2】__to current estimates. To calculate when the【C3】__sea creatures were last seen in Earth’s oceans, the researchers studied every megalodon fossil【C4】__in California and Baja California, Mexico, where the【C5】__of these fish are plentiful. They also studied【C6】_____data on fossils, and found inaccuracies. The results led the researchers to think that the megalodon went extinct much earlier than previously thought.

This calls into【C7】_____past research that suggested the great white shark’s hulking cousin went extinct around 2.6 million years ago. Dr. Robert Boessenecker, study co-author and a vertebrate (脊椎动物) paleontologist at the College of Charleston, commented: “We used the same worldwide dataset as earlier researchers and found that most of the dates had several problems—fossils with dates too young or imprecise, fossils that have been【C8】__, or old dates that have since been refined by improvements in geology; and we now know the【C9】__are much younger. The extinction of Otodus megalodon was previously thought to be related to that of the great white shark—but in reality, we now know the two are not【C10】_____related.”

【C7】