Which phrase best describes a chemical reaction ?

Ex:  mixture and like you know firework which you burn the log became dust cannot be able to change back to orignial form.

The war began as a fight between mayans and the landowners of the country. the main causes of the guatemalan civil war was started by the greed of the united fruit company, the fear of communism, and the racism toward the  mayan  people.

None   they are   equally likely to occur on any plate boundary