Methanogens are responsible for:

Which organism is useful in a biogas plant?

Study the following flow chart of biogas production and select the correct option for $A, B$ and $C$.
Stage $III$: $C$
Stage $II$: Organic acids $\xrightarrow{B}$ $C$
Stage $I$: Soluble compounds or monomers $\xrightarrow{A}$ Organic acids
(Note: The flow chart shows: Proteins,Fats,Cellulose,Hemicellulose $\rightarrow$ Soluble compounds or monomers $\xrightarrow{A}$ Organic acids $\xrightarrow{B}$ $C$)

$A$ - The excreta (dung) of cattle is rich in methanogen bacteria.
$R$ - Thus,dung can be used in biogas production.

Which gas is primarily produced in biogas plants?

Which gases are present in the biogas produced during sewage treatment?