Which statement best describes why industry uses heterogeneous catalysts?
a. they tend to be more stable.
b. they are all gases at room temperature.
c. they form strong bonds with reactant molecules.
d. they cause stronger bonds to form between molecules.

The correct answer is option D, They cause stronger bonds to form between molecules.

Explanation:

Heterogeneous catalysts are used for providing active reacting sites for the molecules. Usually the heterogeneous catalysts are used in a solid state with reactants in liquid and gaseous state. The reactant molecule get adsorbed on the surface of the catalyst and thus with the increased surface area,  the rate of reaction also increases. Also being in a different phase than the reactants helps the catalysts to be easily separated with little expenditure.