Which of the following gases is most abundant in biogas?

Biogas is dominated by methane, which typically makes up more than half of the mixture.

Carbon dioxide is the second largest fraction but stays below methane.

Hydrogen sulphide appears only in trace amounts and gives the foul smell.

Hydrogen is present in negligible quantity if at all.

The high methane share is what makes biogas a usable fuel.

Biogas is generated by anaerobic digestion of animal dung and organic waste.