Answer:
A. Chemical reaction
Explanation:
This is a chemical reaction. A chemical reaction involves the combination of two or more compounds. Such reactions involves the loss and gain or sharing of electrons. For reactions to occur, chemical bonds have to be re-arranged.
The mechanisms of a chemical reaction leads to different effects being produced.
In some chemical reaction, heat is given off and we say it is exothermic. Some absorbs heat. Some reactions liberates gases.
Sometimes in a chemical reaction, light is given off and we say it is chemiluminescent. This is as a result of electrons transiting from one energy level to another.
Reactions that involves transition elements are usually colourful. They are accompanied by a plethora of color changes.
All of these typifies the process of chemical reaction.
