While single celled organisms use the cell surface to (i) ________nutrients from the world outside the system, and to release waste from the organism, multi-celled organisms require a circulatory system and medium of transport for nutrients. Sea-sponges, among the most (ii) __________animals, take advantage of sea-water as a medium of transport, as the sea water flows in and out of the organism it delivers nutrients and removes waste.

Blank (i)	Blank (ii)
A. annex	D. primitive
B. procure	E. vestigial
C. relinquish	F. rudimentary