You can make bread without yeast. It is eaten in many parts of the world, particularly the Middle East. And it tastes very good. The principal difference between this and the bread we are used to eating is that bread made without yeast is flat. It does not rise.
Yeast is a mass of microscopic fungi. They produce tiny bubbles of carbon dioxide. When yeast is mixed with dough, these minute gas bubbles cause it to rise and produce the loaves of bread we buy.
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