Passage 3 Questions 11 to 15 are based on the following passage: Scientists in India have invented a new way to produce electricity. Their invention does not get its power from oil, coal or other fuels, it produces electricity with the power of animals. India has about eighty million bullocks. They do all kinds of jobs. They work in the fields. They pull vehicles through the streets. They carry water containers.(79)Indian energy officials have been seeking ways to use less imported oil to provide energy. Scientists at the National Institute for Industrial Engineering in Bombay(孟买)wondered whether the millions of bullocks could help. Many villages in India lack electricity, but they have many bullocks. And often the animails are not working. One job done by bullocks is to pump water out of the well. The animals do this by walking around and around in a circle. As they walk, they turn a heavy stick that makes the pump move. This technology is centuries old. Scientists thought that the same technology could be used to produce electricity. Bullocks walk in a circle only two or three times a minute. This is much too slow to produce electricity, but it can create enough power to turn a series of gears(齿轮). A large gear sits next to a smaller gear. As the large gear turns it causes the smaller gear to turn. That gear turns an even smaller one. Each gear moves faster because it is a little smaller. The smallest gear may turn extremely fast. (80)clocks operate with gears. So do cars and so does the device invented by he Indian scientists to produce electricity. According to the officials in the United Nations, the idea is being tested at several places in India. The device is easy to operate and repair. And it can be moved easily. It costs about three hundred and seven dollars now to make such a device, but production of large numbers of them could cut the cost of each to about two hundred dollars. why are bullocks used to provide energy in India