The industrialized countries have been depending on 1.(__)like oil and natural gas as well as uranium-based 2.(__)to meet their ever-increasing energy needs. However, there are many problems with them. The eventual 3.(__) of fossil fuels that hitherto proved reliable has left us with no choice but to prepare for a new age of energy 4.(__). Renewable energy alternatives still face various problems though they look 5.(__). Solar energy is unlimited, but is very 6.(__) to use. Wind energy is enormous, but is 7.(__) and expensive to produce. Hydroelectric power is clean, but is environmentally 8.(__). Biomass energy is 9.(__), but is air-polluting and costly. To sum up, an severe 10.(__) is approaching. We must act quickly and work together to find the most effective solutions.