Plant and animal species are categorized under the Endangered Species Act. Which is NOT one of those categories?

The category of "Extinct" is not included under the definitions provided by the Endangered Species Act. Instead, it refers to species that no longer exist anywhere on the planet. The Act focuses on species that are still present but at risk of becoming extinct or severely diminished in population.

The other categories defined by the Act—Extirpated, Endangered, and Threatened—are designed to classify species based on their current status and risk levels. "Extirpated" refers to species that no longer exist in a specific area but may be found elsewhere. "Endangered" describes species that are at risk of extinction throughout all or a significant portion of their habitat. "Threatened" applies to those species that may become endangered in the foreseeable future. Each of these categories plays a crucial role in the conservation efforts outlined by the Act.