Answer 1

Biogas	Natural gas
Formed using organic wastes such as dead plant and animal matter, animal dung and kitchen waste	Found along with petroleum deposits and gets released when crude oil is brought to the surface
Is a non-conventional source of energy	Is a conventional source of energy
Is easily available, especially in rural areas	Is not easily available; very few countries have sufficient natural gas reserves of their own
Is polluting; causes greenhouse effect as it releases carbon dioxide	Is a cleaner fuel
Used as a domestic fuel for cooking and lighting	Used as a domestic fuel as well as an industrial fuel