Enzymes are molecules that act as a catalyst for a chemical reaction. They are proteins in nature and are found and released in body of both plants and animals. They act as spoiling agent in different kinds of food if not eaten/cooked or stored properly within the subsequent shelf life. The most common example is that of banana. The enzymes that are active in banana speed up the process of ripening which cause it to rot/spoil.
This type of spoilage is know as Enzymatic Spoilage.
Bacteria is a tiny living organism, yeast and mold both are fungi while insects are the arthropods which is a class of invertebrates.
Therefore, the correct answer to this question is Enzymes.
It is found in combustion fumes (by cars and trucks), portable generators, wood burning stoves, gas ranges and heating systems. Hope this helps and have a great day! :D
