(N/A) Biogas is considered an ideal fuel for the following reasons:
$(i)$ It has a high calorific value.
$(ii)$ It burns without producing smoke.
$(iii)$ It has a moderate ignition temperature.
$(iv)$ It does not produce harmful residues or toxic gases.
$(v)$ It is cost-effective and easily accessible.
Due to these characteristics:
$(i)$ Biogas serves as an efficient energy source, thereby addressing the fuel crisis.
$(ii)$ Since it burns cleanly, it minimizes air pollution, thus solving environmental problems.
$(iii)$ The use of animal waste and organic matter in biogas plants prevents the contamination of water bodies and soil, further protecting the environment.