Ét o ẻ Ét o ẻ :( mai nộp rồu mấy má ơiii :( Energy is fundamental to (1)... beings. Many poor people in developing countries do not have modern sources of energy like electricity or natural gas, with which their life can be (2)... . People who live in mountainous areas have to gather wood for fuel. This takes a lot of time. For many people living in rural areas, (3)... is the largest energy resource available. The main use of biogas is for cooking and heating, but it can also provide energy for public transport. As biogas is smoke-free, it helps the problem of indoor air (4)... . 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 increase as (5)... ones are running out. In the future, the wind and the sun will be used as the most important environmentally friendly energy sources. Hứa 5* + ctlhn cho má nào sớm + đúng nhất nkaa =))