Therefore, they form one link in the food chain which always begins with the green plant and which leads ultimately to some large animal.
(they; form; one link in the food chain) (the food chain; begins; with the green plant; T:always) (the green plant; leads ultimately; to some large animal)
they the food chain the green plant
form begins leads ultimately
one link in the food chain
with the green plant T:always
to some large animal