Which of the following epochs is NOT part of the Tertiary period?

The Cretaceous epoch is the correct answer because it is not part of the Tertiary period. The Cretaceous is actually the last epoch of the Mesozoic Era, which is known for the dominance of dinosaurs and the development of flowering plants. The Tertiary period follows the Mesozoic Era and encompasses several epochs, including the Paleocene, Eocene, and others, marking an age associated with the rise of mammals and the gradual establishment of modern ecosystems.

In contrast, the Paleocene and Eocene are both epochs that belong to the Tertiary period, characterized by significant evolutionary developments among mammals and birds after the extinction of the dinosaurs. These epochs reflect a time when the Earth's climate and continents were resembling modern conditions more closely.