Biology · MICROBES IN HUMAN WELFARE

The puffed-up appearance of dough used for making foods such as dosa and idli is primarily due to the metabolic activity and production of which of the following gases?

1. A
   Oxygen (\( \text{O}_2 \))
2. B
   Hydrogen sulphide (\( \text{H}_2\text{S} \))
3. C
   Methane (\( \text{CH}_4 \))
4. D
   Carbon dioxide (\( \text{CO}_2 \))