Is yeast used in bread dough natural or synthetic chemical?

Here's why:

* Yeast is a living organism: It's a type of fungus, specifically a single-celled fungus. It's not a chemical compound created in a lab.

* Natural fermentation: Yeast's natural process of consuming sugars and producing carbon dioxide is what causes bread to rise.

* Types of yeast: While there are some cultivated and commercially produced strains of yeast, they are still fundamentally natural organisms.

So, while we might use "chemicals" to describe the process of yeast fermentation, the yeast itself is a natural organism.