"extinct" or "turn extinct"? [closed]
Solution 1:
"Turn extinct" is unusual, and may have been chosen for poetry.
The more usual expression is "go extinct". "Turn" is sometimes used for "become, change state" (eg "turn red", "turn nasty" ="become aggressive or threatening") but would not normally be used with "extinct".
As for your last point, "extinct" is not a verb, so cannot be used on its own there: it needs a verb, normally either "go" or "become".