This water, which living things need to survive, then flows back to sea.
(This water, which living things need to survive; flows; back to sea; T:then) (which living things; need; to survive) Context(which living things need,List([12, 36))):(which living things; need to survive to survive; )
which living things need,List([12, 36))
This water, which living things need to survive which living things which living things
flows need need to survive to survive
back to sea T:then
to survive