Final answer:
The triceratops lived during the Cretaceous period, which spanned from 145.5 to 65.6 million years ago, marking the 'Age of Reptiles'. This period ended with a mass extinction named the 'great dying', which caused the extinction of the triceratops and many other dinosaur species.
Step-by-step explanation:
The triceratops was a large, herbivorous dinosaur that lived during the Cretaceous period of the Mesozoic era. This time period lasted from around 145.5 to 65.6 million years ago. This era, also known as the 'Age of Reptiles', was dominated by dinosaurs. The Cretaceous period ended with a mass extinction event, commonly referred to as the 'great dying', which marked the end of the age of dinosaurs. Most large-bodied animals, including the triceratops, went extinct during this time. Post this event, mammals began to develop and diversify, ultimately leading to the species we see today.
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