Sclerotia are formed by which type of organism and can remain viable in the soil for several years?

Sclerotia are compact masses of hardened fungal mycelium that serve as a survival structure for certain types of fungi. These formations allow the fungi to withstand adverse environmental conditions, such as drought or nutrient scarcity, and they can remain dormant in the soil for extended periods, often several years. The ability to produce sclerotia is a characteristic feature of specific genera of fungi, notably those within the Sclerotiniaceae family, and is essential for their life cycle as it promotes successful establishment and infection of host plants when conditions become favorable.

In contrast, bacteria do not form sclerotia; they typically reproduce through binary fission and can survive in various forms, such as spores, but not specifically as sclerotia. Viruses lack the cellular structure needed to form such structures, relying instead on host cells for replication. Algae, while they can form cysts or other survival forms, do not form sclerotia. Thus, fungi are the organisms that produce sclerotia, making them the correct answer.