What is a resistant structure formed by Gray mold?

The correct answer is the resistant structure known as sclerotia. Sclerotia are hardened masses of mycelium that can survive adverse conditions, serving as a survival mechanism for certain fungi, including those in the genus Botrytis, which is responsible for Gray mold. These structures can persist in the soil for extended periods, enabling the pathogen to survive through unfavorable environmental conditions and later germinate to produce new fungal growth when conditions improve.

Chlamydospores and oospores are also resistant structures that provide survival advantages to other types of fungi but are not specifically associated with Gray mold. Mycelium refers to the network of fungal filaments that is part of the organism's vegetative growth phase but does not represent a specialized structure for long-term survival like sclerotia do. Understanding these distinctions helps clarify the reason sclerotia are highlighted as the primary resistant structure for Gray mold.