Question

Detritus food chain begins with
A. Primary producers
B. Primary consumers
C. Secondary consumers
D. Dead organic matter

Answer 1

Hint: Detritus is the dead organic matter formed of excreta of animals and dead matter of plants and animals and represent the initial stage of decomposition.

Complete step by step answer: Food chain is a series of groups of organisms called trophic levels in which there is repeated eating and eaten by so as to transmit the food energy.
It is of two types- the grazing food chain and the detritus food chain.
Grazing food chain- It is directly dependent on solar radiation as the primary source of energy. Green plants form the first trophic level, herbivores form the second trophic level and carnivores form the third and other trophic levels above it, in this food chain.
Detritus food chain- The primary energy source for this food chain is a dead organic matter called detritus.
Primary consumers are detritivores and it includes protozoans, bacteria, fungi, etc. which feed upon the detritus saprotrophically and thus are called saprotrophs.
This chain is usually shorter than the grazing food chain.
Detritus food chains are very important as the dead organic matter of grazing food chains is decomposed by the detritivores to recycle the inorganic elements into the ecosystem.
In a terrestrial ecosystem, the detritus food chains are more important than the grazing food chains for the energy flow.
So the correct answer is that detritus food chains start with dead organic matter.

Note: So food chains are important for studying the feeding relationship between organisms and they also tell about the energy flow from one trophic level to another trophic level.