Given a context passage, generate a question from the passage such that its answer is shortest continous span from the passage.

Example Input: Everywhere man is altering the balance of nature.He is facilitating the spread of plants and animals into new regions, sometimes deliberately, sometimes unconsciously.He is covering huge areas with new kinds of plants, or with houses, factories, slag-heaps and other products of his civilization.He exterminates some species on a large scale, but favours the multiplication of others.In brief, he has done more in five thousand years to alter the biological aspect of the planet than has nature in five million. Many of these changes which he has brought about have had unforeseen consequences.Who would have thought that the throwing away of a piece of Canadian waterweed would have caused half the waterways of Britain to be blocked for a decade, or that the provision of pot cacti for lonely settlers' wives would have led to Eastern Australian being overrun with forests of Prickly Pear? Who would have prophesied that the cutting down of forests on the Adriatic coasts, or in parts of Central Africa, could have reduced the land to a semidesert, with the very soil washed away from the bare rock? Who would have thought that improved communications would have changed history by the spreading of disease-sleeping sickness into East Africa, measles into Oceania, very possibly malaria into ancient Greece? These are spectacular examples; but examples on a smaller scale are everywhere to be found.We make a nature sanctuary for rare birds, prescribing absolute security for all species; and we may find that some common and hardy kind of bird multiplies beyond measure and ousts the rare kinds in which we were particularly interested.We see, owing to some little change brought about by civilization, the starling spread over the English country-side in hordes.We improve the yielding capacities of our cattle; and find that now they exhaust the pastures which sufficed for less exigent stock.
Example Output: What have spread diseases?

Example Input: New research shows how kids' brains reorganize as they learn math. All the time you spent memorizing multiplication tables may have made you a better mathematician, according to a new study. A team of scientists from Stanford University, in California, have shown how the brain reorganizes itself as kids learn math. After a certain amount of time spent practicing math, kids can put away the calculator . They don't even need to count on their fingers. They simply know the answers to subtraction , addition, and multiplication facts. The quicker kids can recall basic math facts, the easier it is for them to solve more complicated math problems. The Stanford University researchers observed the brain activity of 28 students aged 7to 9 for the study. They took scans of the students' brains as the students solved math calculations without the help of a calculator, pen or paper. A calculation--three plus four equals seven, for example--flashed on a screen. The students pushed a button to say if the answer was right or wrong. The scientists also recorded the response speed, and what parts of the brain became active as the kids pushed the button. These observations showed a process called fact retrieval . Rather than using their fingers to count, or writing out answers on a piece of paper, the students pulled the answers from memory. It's as if the answers to basic math problems are kept in a long-term storage area in the brain, which was built from repetition. "Experience really does matter," said Dr. Kathy Mann Koepeke. Children make the shift from counting to fact retrieval when they are 8 to 9 years old, the study shows. This is the time when most students are learning basic addition and subtraction. When kids have basic math facts memorized, the brain has more free space to learn more complicated math. This process has benefits for the future. The study shows as kids grow older, their answers rely more on memory and become quicker and more accurate. Less brain activity is devoted to counting. Some children make this shift quicker than others.
Example Output: What plays a key role in solving a math problem?

Example Input: Mercury is the smallest planet. It has no moon. The planet is also closest to the Sun and appears in Figure 25.7. As Figure 25.8 shows, the surface of Mercury is covered with craters, like Earths Moon. The presence of impact craters that are so old means that Mercury hasnt changed much geologically for billions of years. With only a trace of an atmosphere, it has no weather to wear down the ancient craters. Because Mercury is so close to the Sun, it is difficult to observe from Earth, even with a telescope. The Mariner 10 spacecraft did a flyby of Mercury in 19741975, which was the best data from the planet for decades. In 2004, the MESSENGER mission left Earth. On its way to Mercury it did one flyby of Earth, two of Venus and three of Mercury. In March 2011, MESSENGER became the first spacecraft to enter an orbit around Mercury. During its year-long mission, the craft will map the planets surface and conduct other studies. One of these images can be seen in Figure 25.9. Mercury is named for the Roman messenger god. Mercury was a messenger because he could run extremely fast. The Greeks gave the planet this name because Mercury moves very quickly in its orbit around the Sun. Mercury orbits the Sun in just 88 Earth days. Mercury has a very short year, but it also has very long days. Mercury rotates slowly on its axis, turning exactly three times for every two times it orbits the Sun. Therefore, each day on Mercury is 58 Earth days long. Mercury is very close to the Sun, so it can get very hot. Mercury also has virtually no atmosphere. As the planet rotates very slowly, the temperature varies tremendously. In direct sunlight, the surface can be as hot as 427C (801F). On the dark side, the surface can be as cold as 183C (297F)! The coldest temperatures may be on the insides of craters. Most of Mercury is extremely dry. Scientists think that there may be a small amount of water, in the form of ice, at the planets poles. The poles never receive direct sunlight. Figure 25.10 shows a diagram of Mercurys interior. Mercury is one of the densest planets. Scientists think that the interior contains a large core made mostly of melted iron. Mercurys core takes up about 42% of the planets volume. Mercurys highly cratered surface is evidence that Mercury is not geologically active. Named after the Roman goddess of love, Venus is the only planet named after a female. Venus is sometimes called Earths sister planet. But just how similar is Venus to Earth? Venus is our nearest neighbor. Venus is most like Earth in size. Viewed through a telescope, Venus looks smooth and featureless. The planet is covered by a thick layer of clouds. You can see the clouds in pictures of Venus, such as Figure 25.11. We make maps of the surface using radar, because the thick clouds wont allow us to take photographs of the surface of Venus. Figure 25.12 shows the topographical features of Venus. The image was produced by the Magellan probe on a flyby. Radar waves sent by the spacecraft reveal mountains, valleys, vast lava plains, and canyons. Like Mercury, Venus does not have a moon. Clouds on Earth are made of water vapor. Venuss clouds are a lot less pleasant. They are made of carbon dioxide, sulfur dioxide and large amounts of corrosive sulfuric acid! The atmosphere of Venus is so thick that the pressure on the surface of Venus is very high. In fact, it is 90 times greater than the pressure at Earths surface! The thick atmosphere causes a strong greenhouse effect. As a result, Venus is the hottest planet. Even though it is farther from the Sun, Venus is much hotter even than Mercury. Temperatures at the surface reach 465C (860F). Thats hot enough to melt lead! Venus has more volcanoes than any other planet. There are between 100,000 and one million volcanoes on Venus! Most of the volcanoes are now inactive. There are also a large number of craters. This means
Example Output:
smallest of all the planets in the solar system