Cooperation

The tongue and nose work together. The tongue is not the only one who 'tastes' your food. The nose is helping also.

Olfactory receptors inside the uppermost part of the nose contain special cells that help you smell. They send messages to the brain.

While you're chewing, the food releases chemicals that immediately travel up into your nose. These chemicals trigger the olfactory receptors inside the nose. They work together with your taste buds to create the true flavour of the food that you are eating.
When you have a cold or allergies, and your nose is stuffy, you might notice that your food doesn't seem to have much flavor. That's because the upper part of your nose isn't clear to receive the chemicals that trigger the olfactory receptors (that inform the brain and create the sensation of flavor).

Try holding your nose the next time you eat something. You will notice that your taste buds are able to tell your brain something about what you're eating - that it's sweet, for instance - but you won't be able to pick the exact flavor until you let go of your nose.