Energy is fundament to human beings. Many poor people in (1)……….... countries do not have modern sources of energy like electricity or natural gas, with which their life can be improved. People who live in mountainous areas have to gather wood (2)……. …fuel. This takes a lot of time. For many people living in rural areas, biogas is the (3)………..energy resource available. The main use of biogas is for ( 4)…………… and heating, but it can also provide energy for public transport. As biogas is smoke-free , its helps the (5)……….... of indoor airpollution. Moreover, it is made from plant waste and animal manure. They cost almost nothing.The tendency to use renewable energy sources in developing countries is on the (6)……...As non- renewable ones are running out. In the future, the wind and the sun will be uses as the most important environmentally friendly energy sources.

Increase             for            developing         largest       cooking           Problem