By studying fossils and rocks, scientists are able to determine what plants and animals lived during different periods and what their environments were like.
(scientists; are; able to determine what plants and animals lived during different periods and what their environments were like) (their environments; were; ) (scientists; to determine; what plants and animals lived during different periods and what their environments were like)
scientists their environments scientists
are were to determine
able to determine what plants and animals lived during different periods and what their environments were like
what plants and animals lived during different periods and what their environments were like