They haven't. They took a huge blow at the end of the Permian but have held on and still exist today.
The scientific name for the Crinoids is (class)Crinoidea.
They are not extinct.
They are not extinct.
They are not extinct.
The are not fully extinct but nearly extinct.
Most become extinct because they can not adapt to changes in their environments. Those that can don't become extinct.
Today's relatives of Crinoids include sea urchins, starfish, sea cucumbers, and brittle stars. Typically, if it looks like a flower, it is a relative of the crinoids.
In years maybe decades the panda will become extinct
No, blondes are just as likely to become extinct as redheads are.
Gorillas are not extinct.
they aren't extinct
Jaguars are not extinct.