Bread is a staple food prepared from a dough of flour (usually wheat) and water, usually by baking. It may be leavened by naturally occurring microbes (e.g. sourdough), chemicals (e.g. baking soda), industrially produced yeast, or high-pressure aeration, which creates the gas bubbles that fluff up bread. In many countries, commercial bread often contains additives to improve flavor, texture, color, shelf life, nutrition, and ease of production.
Throughout recorded history, bread has been a prominent food in large parts of the world. It is one of the oldest human-made foods, having been of significant importance since the dawn of agriculture, and plays an essential role in both religious rituals and secular culture. source: Wikipedia Learn more here