What do termites require in order to digest wood?

Termites rely on a unique relationship with symbiotic microorganisms to effectively digest wood, which is primarily composed of cellulose. The most significant of these microorganisms are protozoa, especially Trichonympha species, which reside within the termite's gut. These protozoa possess the necessary enzymes to break down cellulose into simpler compounds that termites can then absorb and utilize as nutrients.

This mutualistic relationship allows termites to thrive on a diet primarily made up of cellulose, which they would otherwise be unable to digest efficiently on their own. In contrast, while bacteria can also play a role in digestion, the key symbionts in termites that facilitate wood digestion are these protozoa. This specificity underscores the importance of the correct answer as it highlights the essential role of Trichonympha in the termite's digestive process, making it critical to their survival and ecological role as decomposers.

Other options don't capture the primary biological mechanism by which termites process wood, with the mention of improperly treated wood being irrelevant, as it does not contribute to digestion at all.