I was just confused about what this was asking.

This is a topic from kinetics .Here we need to know difference between the catalyst and intermediate.
When you add all reactions, a catalyst and intermediate are not the part of final equation. They cancelled out on adding all reactions.
Now a catalyst is added as reactant first and formed as a product in another reaction.
An intermediate is formed first as product and then reused as the reactant.
 YO₂ is the reactant in first two steps and product in last two steps so YO₂ is the catalyst.
YO is formed in first two steps and used up in last two steps. So YO is the intermediate.

ohh! That makes sense, thank you!