The sentences in the following paragraph have been purposely placed in the wrong order. Examine key terms and transitional devices, and then rearrange the sentences so that the paragraph moves smoothly and logically from one sentence to the next. Indicate the correct order of the sentences by placing the sentence numbers in the order in which the sentences should appear. Briefly explain why you chose that particular order.
(1) If such improvements could be achieved, the consequences would be significant for many different applications. (2) However, the most challenging technical problem is achieving substantial increases in the quantities of electrical energy that can be stored per unit weight of the battery. (3) The overall process yields about 70 percent of the electricity originally put into the battery. (4) A storage battery is a relatively efficient way of storing energy.