Which one among the following statements is not correct ?

Statement 3 is incorrect because primary consumers are heterotrophs, not autotrophs. Autotrophs, such as green plants and phytoplankton, are primary producers that synthesize their own food from inorganic sources like sunlight [4]. Primary consumers, typically herbivores, occupy the second trophic level and must consume these autotrophs to obtain energy [3]. Statement 1 is correct as trophic dynamics involve the transfer of energy through successive levels of a food chain [2]. Statement 2 is accurate because primary production in the deep ocean is nearly nil due to the lack of sunlight for photosynthesis beyond the photic zone, which extends roughly 200 meters [4]. Statement 4 is correct as decomposers, such as fungi and bacteria, are classified as saprotrophs because they break down dead organic matter into simpler substances [1].

Sources

1. [1] Environment and Ecology, Majid Hussain (Access publishing 3rd ed.) > Chapter 12: Major Crops and Cropping Patterns in India > Biotic: Living > p. 119
2. [2] Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 2: Functions of an Ecosystem > z.r.r. Trophic level interaction > p. 11
3. [4] Environment and Ecology, Majid Hussain (Access publishing 3rd ed.) > Chapter 3: MAJOR BIOMES > Food Chains in Marine Biomes > p. 33
4. [3] Science , class X (NCERT 2025 ed.) > Chapter 13: Our Environment > 13.1.1 Food Chains and Webs > p. 210