How is a mycelium formed?

• A. Viruses growing in culture
• B. A mold colony
• C. Individual yeast cells growing on agar
• D. The agglutination of slimy bacterial spores

Answer: (B)

A mycelium is the network of fungal hyphae that makes up the vegetative body of a filamentous fungus. When a mold grows on a substrate, its hyphae extend and branch, intertwining to form this dense, thread-like mass—the mycelium—that underlies the visible mold colony. This is why the correct choice is the mold colony: molds produce a mycelial network, whereas yeasts are unicellular and form individual cells, viruses don’t form cellular colonies, and spore agglutination is a different, non-hyphal process.