Which component of the ecosystem converts inorganic material into org…

The correct answer is Option (4) → Autotrophs

Every ecosystem has living (biotic) and non-living (abiotic) parts. Among the living parts, only autotrophs (green plants and other photosynthetic organisms) can make their own food. They use the radiant energy of the sun to turn simple inorganic substances such as carbon dioxide and water into organic food. All other organisms depend on this food.

Option (1) Consumers — Incorrect. Consumers eat other organisms for food. They use organic matter; they do not make it from inorganic materials.

Option (2) Decomposers — Incorrect. Decomposers do the reverse job: they break dead organic matter down into inorganic substances.

Option (3) Zooplankton — Incorrect. Zooplankton are the consumers of a pond. They feed on phytoplankton and cannot photosynthesise.

Option (4) Autotrophs — Correct. Autotrophs are the producers. They convert inorganic into organic material with the help of sunlight.

NCERT Extract:
Ecosystem – Structure and Function – “… The autotrophic components include the phytoplankton, some algae and the floating, submerged and marginal plants found at the edges. The consumers are represented by the zooplankton, the free swimming and bottom dwelling forms. The decomposers are the fungi, bacteria and flagellates especially abundant in the bottom of the pond. This system performs all the functions of any ecosystem and of the biosphere as a whole, i.e., conversion of inorganic into organic material with the help of the radiant energy of the sun by the autotrophs; consumption of the autotrophs by heterotrophs; decomposition and mineralisation of the dead matter to release them back for reuse by the autotrophs, these event are repeated over and over again.”