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

Input: Consider Input: Oil is a liquid fossil fuel that is extremely useful because it can be transported easily and can be used in cars and other vehicles. Oil is currently the single largest source of energy in the world. Oil from the ground is called crude oil, which is a mixture of many different hydrocarbons. Crude oil is a thick dark brown or black liquid hydrocarbon. Oil also forms from buried dead organisms, but these are tiny organisms that live on the sea surface and then sink to the seafloor when they die. The dead organisms are kept away from oxygen by layers of other dead creatures and sediments. As the layers pile up, heat and pressure increase. Over millions of years, the dead organisms turn into liquid oil. In order to be collected, the oil must be located between a porous rock layer and an impermeable layer (Figure 1.1). Trapped above the porous rock layer and beneath the impermeable layer, the oil will remain between these layers until it is extracted from the rock. Oil (red) is found in the porous rock layer (yellow) and trapped by the impermeable layer (brown). The folded structure has allowed the oil to pool so a well can be drilled into the reservoir. To separate the different types of hydrocarbons in crude oil for different uses, the crude oil must be refined in refineries like the one shown in Figure 1.2. Refining is possible because each hydrocarbon in crude oil boils at a different temperature. When the oil is boiled in the refinery, separate equipment collects the different compounds. Most of the compounds that come out of the refining process are fuels, such as gasoline, diesel, and heating oil. Because these fuels are rich sources of energy and can be easily transported, oil provides about 90% of the energy used for transportation around the world. The rest of the compounds from crude oil are used for waxes, plastics, fertilizers, and other products. Gasoline is in a convenient form for use in cars and other transportation vehicles. In a car engine, the burned gasoline mostly turns into carbon dioxide and water vapor. The fuel releases most of its energy as heat, which causes the gases to expand. This creates enough force to move the pistons inside the engine and to power the car. Refineries like this one separate crude oil into many useful fuels and other chemi- cals. Click image to the left or use the URL below. URL: The United States does produce oil, but the amount produced is only about one-quarter as much as the nation uses. The United States has only about 1.5% of the worlds proven oil reserves, so most of the oil used by Americans must be imported from other nations. The main oil-producing regions in the United States are the Gulf of Mexico, Texas, Alaska, and California (Figure As in every type of mining, mining for oil has environmental consequences. Oil rigs are unsightly (Figure 1.4), and spills are too common (Figure 1.5). Click image to the left or use the URL below. URL: Offshore well locations in the Gulf of Mex- ico. Note that some wells are located in very deep water. Drill rigs at the San Ardo Oil Field in Monterey, California.

Output: crude oil is a mixture of many different

Input: Consider Input: Singapore did not have a native population in the true sense of the word as the population became dominated numerically by three main groups of immigrants after the British founded Singapore as a free port in the 19th century. It was estimated that when Raffles arrived in Singapore in January 1819, Singapore had about 120 Malays, 30 Chinese and some local tribes (the Orang Laut) under the rule of the Temenggung. Around 100 of these Malays had originally moved to Singapore from Johor in 1811 led by the Temenggung. Another estimate put the total population of the whole of Singapore at 1,000, mostly of various local tribes. Early census figures of Singapore show a long period of influx of migrant workers into the country, initially mostly Malays, quickly followed by the Chinese. By 1821, the population was estimated to have increased to 4,724 Malays and 1,150 Chinese. In the first census of 1824, 6,505 out of the 10,683 total were Malays and Bugis, constituting over 60% of the population. Large number of Chinese migrants started to enter Singapore just months after it became a British settlement, and they were predominantly male. In 1826, official census figures give a total population of 13,750, with 6,088 Chinese, 4,790 Malays, 1,242 Bugis, 1,021 Indians from Bengal (244) and the Coromandel Coast (777), smaller number of Javanese people (267), Europeans (87) and other peoples. The population total of Singapore increased to 16,000 in 1829, 26,000 five years later. By 1836, the Chinese at 13,749 had become the most populous ethnic group, overtaking the broad Malay grouping (12,538, including other groups such as the Bugis, Javanese, and Balinese). By the beginning of 1850, the population had reached 60,000, 24,790 of them Chinese.

Output: What was the nationality of Raffles?

Input: Consider Input: A new study found that inner-city kids living in neighborhoods with more green space gained about 13% less weight over a two-year period than kids living among more concrete and fewer trees. Such findings tell a powerful story. The obesity epidemic began in the 1980s, and many people think it results from increased portion sizes and inactivity , but that can't be everything. Big Macs and TVs have been with us for a long time. "Most experts agree that the changes were related to something in the environment," says Thomas Glass of the Hopkins School of Public Health. That something could be a shrinking of the green. The new research, published in the American Journal of Preventive Medicine, isn't the first to associate greenery with better health, but it does get us closer to identifying what works and why. At its most straightforward, a green neighborhood simply means more places for kids to play -- which is important since time spent outdoors is one of the strongest links to children's activity levels. Glass warns that most studies don't necessarily prove a link between greenness and health, but they're helping _ action. In September the U.S. government approved the No Child Left Inside Act to encourage public initiatives aimed at exposing kids to the outdoors. Finding green space is, of course, not always easy, and you may have to work a bit to get your family a little grass and trees. If you live in a suburb or a city with good parks, take advantage of what's there. Your children in particular will love it -- and their bodies will thank you.
Output: According to the passage, what might cause children's inactivity?