The rate of decomposition is controlled by:

Both chemical composition of detritus and climatic factors

The correct answer is Option (3)- Both chemical composition of detritus and climatic factors

The rate of decomposition, the process by which organic matter is broken down into simpler substances by microorganisms, is influenced by various factors. Among these, the primary ones are the chemical composition of detritus (organic matter being decomposed) and climatic factors. Decomposition is largely an oxygen-requiring process. The rate of decomposition is controlled by chemical composition of detritus and climatic factors. In a particular climatic condition, decomposition rate is slower if detritus is rich in lignin and chitin, and quicker, if detritus is rich in nitrogen and water-soluble substances like sugars. Temperature and soil moisture are the most important climatic factors that regulate decomposition through their effects on the activities of soil microbes. Warm and moist environment favour decomposition whereas low temperature and anaerobiosis inhibit decomposition resulting in build up of organic materials