Diagram of a concept map that displays multiple heirarchal levels. At the top is Reactions, which leads to two circles for how reactions can be classified. One of the circles says chemical reactions, and the other circle is blank. The blank circle leads down to three more circles below it. The left circle says fission, the middle is blank, and the right says nuclear decay. The circle with nuclear decay leads down to three more circles below it. The circle on the left says alpha particles, and the middle and right circles are blank.