1. disappearance
We reported his disappearance.
We have to look into the disappearance of the doctor.
The police are looking into his disappearance.
Scientists are debating his theory about the disappearance of the dinosaurs.
The mistery of her disappearance was never solved
But they said he wasnt a suspect in his wifes disappearance.
Her disappearance is a great mystery.
2. extinction
Global climatic changes may have been responsible for the extinction of the dinosaurs.
They are in danger of extinction.
Some wild animals are on the verge of extinction.
Many fragile species are on the verge of extinction.
The Siberian tiger is on the verge of extinction.
Due to total russification in Belarus, the Belarusian language is at the brink of extinction.
There are many theories about the sudden extinction of the dinosaurs, but the real cause still remains anyone's guess.
Imogen of the Internet has created a seminal classification of thirty distinct varieties of chatspeak, some now facing linguistic extinction.
Many of the world's seven thousand or so languages are spoken only by handfuls of living people and are in danger of extinction.
Extinction is part of evolution.