Which one of the following organisms is dependent on saprophytic mode of nutrition?

Agaricus, commonly known as the mushroom, is a member of the Kingdom Fungi and depends on a saprophytic mode of nutrition [1]. Saprophytes are heterotrophic organisms that obtain their nutrients by breaking down dead and decaying organic matter, such as soil humus or rotting wood, using extracellular enzymes [2]. In contrast, Ulothrix and Cladophora are filamentous green algae that possess chlorophyll and are primarily autotrophic, producing their own food through photosynthesis. Riccia is a liverwort (bryophyte) which is also autotrophic and contains chlorophyll for photosynthesis. Fungi like Agaricus lack chlorophyll entirely, making them dependent on external organic sources for energy [2]. Therefore, among the given options, only Agaricus exhibits the saprophytic strategy essential for nutrient cycling in ecosystems.

Sources

1. [1] Science , class X (NCERT 2025 ed.) > Chapter 5: Life Processes > 5.2.2 Heterotrophic Nutrition > p. 84
2. [2] Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 9: Indian Biodiversity Diverse Landscape > 2. Fungi: > p. 156