An index fossil allows a scientist to determine the age of the rock it is in.
(it; is; in) (An index fossil; allows; a scientist to determine the age of the rock) Context(An index fossil allows,List([0, 22))):(a scientist; to determine; the age of the rock)
An index fossil allows,List([0, 22))
it An index fossil a scientist
is allows to determine
in
a scientist to determine the age of the rock
the age of the rock