Of course! Biological leavening agents, such as yeast, are indeed natural and work through the process of fermentation. Fermentation is a metabolic process where microorganisms, such as yeast, break down sugars in food, such as bread dough, and convert them into other compounds, including carbon dioxide gas and flavor compounds.
In the case of bread-making, yeast is added to the dough, and as it feeds on the sugars present in the dough, it produces carbon dioxide gas. This gas gets trapped in the dough, causing it to rise or "leaven." The release of carbon dioxide gas during fermentation is what gives bread its fluffy and light texture.
It's worth mentioning that yeast is a type of fungus that occurs naturally in the environment and can be used in cooking to facilitate the leavening process. So, when we say that biological leavening agents are natural, we mean that they are derived from natural sources, like yeast, and not artificially synthesized chemicals.
Therefore, the statement "Biological leavening agents are natural and work through the fermentation of sugar in food" is true.