What exactly is yeast? Why does everyone say yeast is good for pasta?

Yeast is a fungus called Saccharomyces cerevisiae.

All pasta is actually made using yeast.

Yeast is a parthenogenetic anaerobic fungus that can utilize sugar for anaerobic respiration to produce alcohol and carbon dioxide in an anoxic environment. The carbon dioxide produced causes a hole to appear in the dough, and that's when we say the dough rises.

People used to make dough with old flour, which actually contains a lot of yeast.

Yeast is not only used in dough making, but also in brewing and other industries.

Yeast can even be used as a digestive aid.