← Biology Export Options Alphabetize Word-Def Delimiter Tab Comma Custom Def-Word Delimiter New Line Semicolon Custom Data Copy and paste the text below. It is read-only. Select All Energy The ability to move or change matter. Activation Energy The energy that is needed to start a chemical reaction. Enzymes Substances that increase the speed of chemical reactions. Substrate A substance on which an enzyme acts during a chemical reaction. Atom The smallest unit of matter that cannot be broken down by chemical means.