Which of the following questions can be answered by science? What is the composition of air? Should the driving age be reduced? What is the purpose of our existence on Earth? Should students be allowed to bring toys to school?

Which statement is true about a catalyst? a: a catalyst decreases the rate of the reaction. b. a catalyst is consumed during a chemical reaction. c. a catalyst lowers the activation energy of a reaction. d. a catalyst increases the reactant concentration during a reaction.