What essential nutrient do termites primarily acquire from their symbiotic relationship with protozoans?

Termites primarily acquire cellulose from their symbiotic relationship with protozoans. This relationship is vital because termites themselves lack the enzymes necessary to break down cellulose, a complex carbohydrate found in plant cell walls. The protozoans residing in the termite gut are able to digest cellulose and convert it into simpler compounds that the termites can absorb and utilize for energy. This interaction not only allows termites to exploit a food source that would otherwise be indigestible, but it also highlights the importance of symbiosis in ecological systems, demonstrating how organisms can work together to thrive in their environments. Thus, cellulose is the essential nutrient that is effectively processed and made available to termites through this unique relationship.