Extinct species are those that

(a) are abundant

(b) live only in zoos

(c) no longer exist

(d) migrate seasonally

Correct answer: (c) No longer exist

Extinct species are those for which there is no reasonable doubt that the last individual has died. After exhaustive surveys in known and expected habitats, at appropriate times, and across the species’ historic range, no living members are found—neither in the wild nor in captivity. Once a species is extinct, it is lost from Earth’s biodiversity forever.

• Definition: Zero surviving individuals anywhere (wild or captivity).
• Examples:Dodo (Mauritius), Passenger pigeon (North America), Thylacine/Tasmanian tiger (Australia).
• Common causes: Habitat destruction, overhunting/poaching, invasive species, pollution, and rapid climate change.
• Why it matters: Extinction reduces ecosystem stability, erases unique genes/traits, and signals broader environmental stress.

Eliminate the other options

• (a) Are abundant – Opposite of extinct; abundant species have large populations.
• (b) Live only in zoos – Describes “Extinct in the Wild”, not extinct. Such species survive only in captivity or cultivation (no wild populations).
• (d) Migrate seasonally – Refers to migratory species, not extinction status.

Final answer: (c) No longer exist.