One reason that bacteria can be harmful is that they: a. can remove nitrogen gas from the air. b. have cell walls with peptidoglycan. c. can produce toxins that kill other cells. d. live in the digestive tracts of animals.

Use the drop-down menus to match each part of the scenario to the correct scientific practice. akira records the speed of a reaction without a catalyst and then with a catalyst. akira creates a reaction without a catalyst and repeats the reaction with a catalyst. akira turns in a written lab report to his science teacher. akira wonders, "will adding a catalyst speed up this chemical reaction? " akira writes in his notes that adding a catalyst sped up the chemical reaction because the catalyst lowers the activation energy needed to get the reaction started.