List two ways in which animal dung can be utilized as a fuel. Out of these two which one do you think is better ? Justify your answer.

Explanation

Two ways:
(i) as cow dung cakes,
(ii) as biogas.
Biogas is better than cow dung cakes because it has high heating capacity and are non-polluting as it burns without smoke and leaves no residue like ash. Slurry left in the biogas plant is a good manure for fields.