Question

What is the difference between threatened, endangered, and extinct species?

Answer 1

Threatened means the species isn’t quite endangered yet. It is close to being endangered.
Endangered species means the species has a low population left in the world and it’s about to be near extinction.
Extinct species means the species are all dead, they don’t exist any more, population= 0

Answer 2

Threatened means they are lowering in numbers and nearing to be endangered. 

Endangered means they are dangerously close to being extinct

Extinct means there is none of them left in the wild. 

I hope this is what you meant.