The detritus food chain (DFC) has _____ at the first tropic level.

Dead organic matter

The correct answer is Option (2) → Dead organic matter

The detritus food chain (DFC) begins with dead organic matter.  It is made up of decomposers which are heterotrophic organisms, mainly fungi and bacteria. They meet their energy and nutrient requirements by degrading dead organic matter or detritus. These are also known as saprotrophs (sapro: to decompose). Decomposers secrete digestive enzymes that break down dead and waste materials into simple, inorganic materials, which are subsequently absorbed by them.