Flow diagram that shows the heirarchal relationship of the types of reactions. A box titled Types of Reactions is at the top of the diagram. Beneath it are four subtopics in boxes. The left box says Synthesis. The left-center box is blank with a question mark. The right-center box says Single Replacement. The right box is blank with a question mark. Each of the four boxes leads to a lower box in the diagram. The Synthesis box leads to a box with an equation that says A plus B leads to AB. The other boxes are blank with question marks.