Living things
Extinct means there are no living members of the species. For example, the dodo bird is extinct. Dodo birds are extinct because they have all been killed and there are none left to continue the species.
Species can become extinct naturally, or by the action of a new or introduced species, or by human activities such as loss of habitat or over hunting.
Geology
A volcano that is not expected to erupt again can be called "extinct" as opposed to "dormant" meaning that it could possibly erupt again.
like animals after a while it goes extinct which means no more species of that kind and will not come again for that species
The definition of extinct is the end of an organism or group of organisms, normally a species.
it means that there is no more left in the world. that is extinct
means non living anymore like fossils
No longer exists.
I'm not sure if you mean extinction, or extension, but there you have both.
No longer in existence
If you mean on the brink of extinction then no.
It means complete destruction; annihilation
Functional extinction means that there are not enough live animals (or animal protoplasm) of a certain species for the species to breed and survive.
New species that form right after a mass extinction
The absence of any reinforcement following a behavior. Usually extinction occurs in situations where positive reinforcement was formerly applied.
(of flora or fauna) in imminent danger of extinction; "an endangered species"
limited amount and close to extinction
Is extinction the word you're looking for ?
the answer to the question is extinction
No, mule deer are not threatened by extinction, if that's what you mean by are mule threatened. If you mean are mule deer threatened by other animals, then yes, they are threatened by other animals. They are threatened by their predators, such as cougars and coyotes, but not by extinction.