(a) Producers serve as a source of food in a grazing food chain and constitute the first trophic level and serve to incorporate nutrients into the body of living organisms whereas detritus food chain begins with detritivores that feed on the dead and decaying matter and serves to release the nutrients back into the atmosphere.(b) Production refers to the rate of synthesis of organic matter by primary producers through the process of photosynthesis while decomposition refers to the breakdown of complex substances into simpler ones and is carried out by heterotrophic decomposers. (c) Number and biomass of producers are largest and gradually decreases while moving from primary consumers to top consumers; it gives upright pyramid while Inverted pyramids exhibit lowest quantity of selected attribute at producer level. (e) Litter constitutes both biodegradable and nonbiodegradable waste while detritus is the only biodegradable waste.(f) Primary productivity refers to the total organic matter produced by primary producers per unit area per unit time while secondary productivity refers to rate conversion of food molecules into biomass at consumer level per unit area per unit time.