With reference to the food chains in ecosystems, which of the following kinds of organism is/are known as decomposer organism / organisms? 1. Virus 2. Fungi 3. Bacteria Select the correct answer using the codes given below.

In an ecosystem, decomposers (or saprotrophs) are organisms that break down dead organic matter from plants and animals into simpler inorganic substances [2]. This process is essential for nutrient recycling, as it releases materials like carbon dioxide and nitrogen back into the soil and atmosphere for reuse by producers [4]. Bacteria and fungi are the primary decomposers in most food chains [5]. They operate by secreting enzymes to break down complex organic molecules and absorbing the nutrients on a molecular scale [5]. While fungi dominate decomposition in environments like streams and wetlands, bacteria are key mineralizers in aquatic zones. Viruses are not considered decomposers; they are obligate intracellular parasites that require a living host to replicate and do not perform saprotrophic nutrition or independent metabolic breakdown of detritus. Therefore, only fungi and bacteria are classified as decomposer organisms.

Sources

1. [1] Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 1: Ecology > ii) Micro consumers - Saprotrophs (decomposers or osmotrophs) > p. 7
2. [2] Environment and Ecology, Majid Hussain (Access publishing 3rd ed.) > Chapter 1: BASIC CONCEPTS OF ENVIRONMENT AND ECOLOGY > Decomposers or Saprophytes > p. 30
3. [3] Environment and Ecology, Majid Hussain (Access publishing 3rd ed.) > Chapter 1: BASIC CONCEPTS OF ENVIRONMENT AND ECOLOGY > Decomposers or Saprophytes > p. 31
4. [4] Science , class X (NCERT 2025 ed.) > Chapter 13: Our Environment > Activity 13.1 > p. 209
5. [5] Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 29: Environment Issues and Health Effects > 29.3.4. Greeenwashing > p. 421