Main Page | See live article | Alphabetical index In science, reaction is closely realted to Newton's third law: "For every action there is an equal and opposite reaction". The idea that any given force has a pair or opposite force. This law has often been applied to social sciences, and is a basic premise of the popular Game theory. A reaction is any responsed caused by some other action. There are many different types of reactions: Chemical reaction Reflex reaction light reaction Hill reaction This article is from Wikipedia. All text is available under the terms of the GNU Free Documentation License.