With reference to the food chains in ecosystems, which of the following kinds of organism is/are known as decomposer organism/organisms?

Correct Option (B)

Fungi and Bacteria are essential decomposer organisms in ecosystems. They obtain nutrients by breaking down dead organic matter, such as dead plants, animals, and their waste products. This process of decomposition releases inorganic nutrients back into the soil and water, making them available for producers (plants). This crucial role ensures the recycling of matter and the continuous flow of energy within the ecosystem.

Incorrect Options

Viruses are obligate intracellular parasites. They replicate by infecting living host cells and utilizing the host's cellular machinery. While viruses can cause the death of host organisms, they do not actively break down dead organic matter to derive nutrition or recycle nutrients in the manner of decomposers. Therefore, viruses are not classified as decomposer organisms. Options (A), (C), and (D) are incorrect as they include viruses.