ZnO(s) + C(s) -> Zn(s) +CO(g), in this reaction, carbon is an example of a ____.

The removal of oxygen from a substance is called reduction. Metal oxides get reduced to corresponding metals by using suitable reducing agents such as carbon. In the given reaction, the metal oxide, that is Zinc oxide is getting converted into zinc metal in the presence of carbon atom. In other words, it is the carbon which is reducing the zinc oxide to metal zinc. So, here carbon is an example of a reducing agent.