Final answer:
In a redox reaction, the reductant loses electrons and is oxidized, while the oxidant gains electrons and is reduced.
Step-by-step explanation:
In any electrochemical process, electrons flow from one chemical substance to another, driven by an oxidation-reduction (redox) reaction. A redox reaction occurs when electrons are transferred from a substance that is oxidized to one that is being reduced. The reductant is the substance that loses electrons and is oxidized in the process; the oxidant is the species that gains electrons and is reduced in the process.