Question

In a hydrogen- oxygen fuel cell

hydrogen diffuses through the cathode.
hydrogen and oxygen are mixed before entering the anode.***
oxygen diffuses through the anode.
oxygen diffuses through the cathode.

Answer 1

https://en.wikipedia.org/wiki/Fuel_cell

http://www.bluffton.edu/courses/TLC/MontelA/Montel/Alternative_Energy_Website/Fuel_Cell.htm