Final answer:
In the given reaction CO₂ + H₂ → CO + H₂O, the species that is oxidized is carbon monoxide (CO).
Step-by-step explanation:
In the given reaction CO₂ + H₂ → CO + H₂O, the species that is oxidized is carbon monoxide (CO). Oxidation refers to the loss of electrons or an increase in oxidation state. In this reaction, carbon in CO has an oxidation state of +2, while in CO₂, it has an oxidation state of +4. Therefore, carbon in CO is undergoing oxidation.