Wheat contains gluten but rye and barley also contain gluten. Gluten is a protein found in grains. People with Celiac's disease are allergic to wheat and gluten. Tapioca and spelt are examples of...
No, a potato is a potato. If you are curious about instant mashed, Idaho Potatoes are clearly labeled on the back on the gluten free varieties.
Yes, it has a very high content of gluten.
according to celiac.com, it does contain gluten: http://www.celiac.com/gluten-free/index.php?showtopic=42255
I think so. Most products, anyways.