Which gas is released during the process of fermentation that gives the puffy appearance to dough for making bread?

Statement $X$: $LAB$ (Lactic Acid Bacteria) is very useful for the digestive system.
Statement $Y$: $LAB$ protects us from harmful bacteria in the stomach.

Which acid is produced during the fermentation of sour fruits in the preparation of pickles?

Which microbes are responsible for making curd from milk?

Which of the following converts milk into curd and increases the amount of vitamin $B_{12}$?

Roquefort cheese is ripened by