Final answer:
The Cretaceous period was named after the Latin word for 'chalk.' It lasted from 145 to 66 million years ago and is known for its diverse dinosaurs and chalk formations.
Step-by-step explanation:
The Cretaceous period was named from the Latin word "creta," which means chalk. The period spanned from about 145 to 66 million years ago and is known for its diverse group of dinosaurs and the widespread presence of chalk formations. Chalk is a soft, white, porous sedimentary rock composed mainly of the remains of microscopic marine organisms called coccolithophores.
During the Cretaceous period, the continents were close to their current positions, and Earth's climate was warm, with no polar ice. The period ended with a mass extinction event that marked the end of the dinosaurs.