Final answer:
When a loaf of bread has large, over expanded cells, it means that too much yeast was added to the dough.
Step-by-step explanation:
When a loaf of bread has large, over expanded cells, it means that too much yeast was added to the dough. Yeast is a microorganism that produces carbon dioxide gas as it ferments sugar in the dough, causing the dough to rise. When too much yeast is added, the dough rises too quickly and the gas bubbles expand excessively, resulting in large, over expanded cells in the bread.