Correct Option
The correct option is Exothermic.
Explanation
Chemical reactions are classified based on the exchange of energy between the system and the surroundings. Exothermic reactions are those in which energy is released, typically in the form of heat. Endothermic reactions are those in which energy is absorbed from the surroundings.
Detailed Analysis
The decomposition of vegetable matter into compost is a biochemical process driven by microorganisms such as bacteria and fungi. These microbes break down complex organic compounds (carbohydrates, proteins, etc.) found in vegetable matter into simpler substances.
During this breakdown process, chemical bonds are severed, releasing energy in the form of heat. This release of heat is why compost piles often maintain a temperature significantly higher than the ambient air. Since heat is evolved during the reaction, it is classified as an exothermic reaction.
Key Takeaway
The decomposition of organic matter is an exothermic process because it involves the breakdown of complex molecules, resulting in the release of heat energy.