Which group consists entirely of organic molecules

An organic compound is a compound of which one of the constituent chemical elements is carbon. This compound can be of natural origin (for example CO2, proteins, carbohydrates, lipids and nucleic acids) or produced by synthesis (aliphatic such as ethane and hexane, or cyclic such as cyclohexane and benzene) .

It is useful, beforehand, to distinguish organic compounds from inorganic compounds (such as water and oxygen).

good thing- during decomposition the organic molecules in organic matter are broken down into simpler organic molecules that require further decomposition or into mineralised nutrients

bad thing- it can be harmful in crop productivity