______ species are the species which are not found after searches of known or likely areas where they may occur.

Extinct

The correct answer is Option (1) - Extinct

The term that fits the given definition is: Extinct

Extinct species are those that are no longer found after searches of known or likely areas where they may occur. These species have completely disappeared from the Earth, typically due to natural causes, habitat destruction, overhunting, or other human activities. Extinction is a natural part of the evolutionary process, but human activities have accelerated the rate of extinction in recent times. Extinction means that the entire population of a species has died out, and there are no individuals left to reproduce. As a result, extinct species are considered to be lost forever unless brought back through techniques such as cloning or de-extinction efforts.