Detritivores are organisms that feed on dead organic matter, contributing to nutrient recycling in ecosystems. Earthworms, millipedes, and woodlice are all classified as detritivores because they consume decomposed plant and animal matter, facilitating decomposition and soil aeration. In contrast, jellyfish and seahorses do not play this role; jellyfish are primarily planktonic predators, and seahorses are carnivorous fish that feed on small prey, thus excluding them from the detritivore category. This understanding is fundamental in the study of ecological interactions and energy flow within ecosystems, which is a key concept in UPSC GS Paper I.