Answer
See work below.
Work Step by Step
Most modern animals use iron in hemoglobin to transport oxygen through their bloodstreams, and a few (such as lobsters) use copper for this function. However, some extinct animals used vanadium. Even today, one group of simple marine organisms, the tunicates, are believed to employ vanadium compounds for oxygen transport. The source of vanadium in some crude oil may be the very animals from which the oil was formed.
