The children create a mobile of their favourite food chain beginning with the Sun and ending with themselves, a lion, a killer whale and so on.
(The children; create; a mobile of their favourite food chain beginning with the Sun and ending with themselves, a lion, a killer whale and so on) (themselves; [is]; a lion)
The children themselves
create [is]
a mobile of their favourite food chain beginning with the Sun and ending with themselves, a lion, a killer whale and so on
a lion