Their most distinguishing physical feature is the claw-like forceps on the end of their abdomen, which are used for protection or capturing prey.
(Their most distinguishing physical feature; is; the claw-like forceps on the end of their abdomen) (their abdomen; are used; for protection or capturing prey)
Their most distinguishing physical feature their abdomen
is are used
the claw-like forceps on the end of their abdomen
for protection or capturing prey