(N/A) Microbes release gases during metabolism,which can be demonstrated through the following examples:
$1$. Fermentation in Dough: The dough used for making foods like $Idli$ and $Dosa$ is fermented by bacteria. During this metabolic process,bacteria release $CO_2$ gas. This gas gets trapped in the dough,causing it to puff up or rise.
$2$. Fermentation by Yeast: Yeast ($Saccharomyces$ $cerevisiae$) performs fermentation on sugars to produce alcohol and $CO_2$. The chemical reaction is:
$Glucose \xrightarrow{\text{Without oxygen}} Alcohol + Energy + CO_2$
These examples confirm that metabolic activities of microbes,such as fermentation,result in the production and release of gases like $CO_2$.