The structural integrity of wood may be destroyed by which of the following organisms?

• A. Decaying fungi
• B. Bacteria
• C. Moss
• D. Sunlight

Answer: (A)

Wood’s strength fails most because of wood-decay fungi. These fungi release powerful enzymes that break down cellulose and lignin, the key structural components of wood. As they digest these polymers, the wood develops tunnels, cracks, and hollowing, losing stiffness and load-bearing capacity. They need moisture and oxygen, so damp timber is especially at risk.

Bacteria can contribute to decay, but they generally don’t cause the same level of structural weakening as fungi. Moss simply grows on the surface and doesn’t chemically destroy wood, and sunlight isn’t an organism that destroys wood structure ( though it can affect finishes or dry out wood over time).