Some scientists call them &quot;living fossils&quot; because they have survived relatively unchanged for at least 50 million years.
(Some scientists; call; them; because they have survived relatively unchanged for at least 50 million years) (they; have survived relatively unchanged; T:for at least 50 million years)
Some scientists they
call have survived relatively unchanged
them because they have survived relatively unchanged for at least 50 million years
T:for at least 50 million years