Which of the following is always involved in a scientific inquiry?
a.
conducting surveys to ask people's opinions on various subjects
b.
developing solutions to questions through scientific research
c.
knowing the correct answer before you start
d.
guessing what would happen instead of doing experiments

Platinum is a Heterogeneous catalyst  

Explanation:

Catalyst are substance that speed up the rate of a chemical reaction . Catalyst increases the rate of a chemical reaction by lowering it activation energy. During the reaction, the catalyst are not consumed. In other words, catalyst does not change in amount as it does not go into the reaction.

Catalyst can be homogeneous or heterogeneous . A homogeneous catalyst is one which phase(liquid or gas) is same as the reactant phase. Heterogeneous catalyst are catalyst which phase(solid) is different from the reactants phase.      

From the reaction above

2H2O(aq)    Pt(s)→    2H2O(l) + O2(g)

Platinum is at the solid phase which is a different phase from the reactant(Hydrogen peroxide) which is Aqueous.

Since platinum is of a different phase , it is a heterogeneous catalyst.