Final answer:
Metallothionein is the main transport vehicle for zinc in the blood, playing a role in the synthesis of hemoglobin.
Step-by-step explanation:
The main transport vehicle for zinc in the blood is the protein metallothionein. Zinc functions as a co-enzyme that facilitates the synthesis of the heme portion of hemoglobin, which delivers oxygen to the body and removes carbon dioxide. Zinc is also involved in various other biological processes in the body.