Which of the following is the rate-limiting factor in biogas production?

Assertion $A$: Herbivores release methane gas into the atmosphere.
Reason $R$: Herbivores consume a cellulose-rich diet.
Which option is correct for Assertion $A$ and Reason $R$?

Which of the following is responsible for the production of biogas?

The technology of biogas production was developed in India due to the efforts of

The type of gases produced during the process in biogas plants depends on which of the following?

The diagram below represents a typical biogas plant. Select the correct option for what $A$,$B$,and $C$ refer to.