Which of the following statements is true about catalysts? (1 point) a. catalysts slow down the rate of chemical reactions. b. all catalysts are enzymes c. catalysts are used up during a chemical reaction. d. catalysts lower the activation energy of a chemical reaction.

What is genetic variation? -(a) each individual in a population has slightly different genes. -(b) some individuals in a population have more genes than others. -(c) each population of a species has slightly different genes. -(d)some populations of a species have more genes than others.