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

Example Input: Grant Heslov (born May 15, 1963) is an American actor, film producer, screenwriter and director, known for producing Argo (2012) for which he received an Academy Award for Best Picture as co-producer in 2013.
Example Output: What was Grant Heslov nominated for?

Example Input: Humans use six times as much water today as they did 100 years ago. People living in developed countries use a far greater proportion of the worlds water than people in less developed countries. What do people use all of that water for? Besides drinking and washing, people need water for agriculture, industry, household uses, and recreation (Figure Water use can be consumptive or non-consumptive, depending on whether the water is lost to the ecosystem. Non-consumptive water use includes water that can be recycled and reused. For example, the water that goes down the drain and enters the sewer system is purified and then redistributed for reuse. By recycling water, the overall water consumption is reduced. Consumptive water use takes the water out of the ecosystem. Can you name some examples of consumptive water use? Some of the worlds farmers still farm without irrigation by choosing crops that match the amount of rain that falls in their area. But some years are wet and others are dry. For farmers to avoid years in which they produce little or no food, many of the worlds crops are produced using irrigation. Water used for home, industrial, and agricultural purposes in different regions. Globally more than two-thirds of water is for agriculture. Three popular irrigation methods are: Overhead sprinklers. Trench irrigation: canals carry water from a water source to the fields. Flood irrigation: fields are flooded with water. All of these methods waste water. Between 15% and 36% percent of the water never reaches the crops because it evaporates or leaves the fields as runoff. Water that runs off a field often takes valuable soil with it. A much more efficient way to water crops is drip irrigation (Figure 1.2). With drip irrigation, pipes and tubes deliver small amounts of water directly to the soil at the roots of each plant or tree. The water is not sprayed into the air or over the ground, so nearly all of it goes directly into the soil and plant roots. Why do farmers use wasteful irrigation methods when water-efficient methods are available? Many farmers and farming corporations have not switched to more efficient irrigation methods for two reasons: 1. Drip irrigation and other more efficient irrigation methods are more expensive than sprinklers, trenches, and flooding. 2. In the United States and some other countries, the government pays for much of the cost of the water that is used for agriculture. Because farmers do not pay the full cost of their water use, they do not have any financial incentive to use less water. What ideas can you come up with to encourage farmers to use more efficient irrigation systems? Aquaculture is a different type of agriculture. Aquaculture is farming to raise fish, shellfish, algae, or aquatic plants (Figure 1.3). As the supplies of fish from lakes, rivers, and the oceans dwindle, people are getting more fish from aquaculture. Raising fish increases our food resources and is especially valuable where protein sources are limited. Farmed fish are becoming increasingly common in grocery stores all over the world. Workers at a fish farm harvest fish they will sell to stores. Growing fish in a large scale requires that the fish stocks are healthy and protected from predators. The species raised must be hearty, inexpensive to feed, and able to reproduce in captivity. Wastes must be flushed out to keep animals healthy. Raising shellfish at farms can also be successful. For some species, aquaculture is very successful and environmental harm is minimal. But for other species, aqua- culture can cause problems. Natural landscapes, such as mangroves, which are rich ecosystems and also protect coastlines from storm damage, may be lost to fish farms (Figure 1.4). For fish farmers, keeping costs down may be a problem since coastal land may be expensive and labor costs may be high. Large predatory fish at the 4th or 5th trophic level must eat a lot, so feeding large numbers of these fish is expensive and environmentally costly. Farmed fish are genetically different from wild stocks, and if they escape into the wild they may cause problems for native fish. Because the organisms live so close together
Example Output: water that can be recycled and reused is called ____________water use.

Example Input: Radioactive decay is the breakdown of unstable elements into stable elements. To understand this process, recall that the atoms of all elements contain the particles protons, neutrons, and electrons. An element is defined by the number of protons it contains. All atoms of a given element contain the same number of protons. The number of neutrons in an element may vary. Atoms of an element with different numbers of neutrons are called isotopes. Consider carbon as an example. Two isotopes of carbon are shown in Figure 11.15. Compare their protons and neutrons. Both contain 6 protons. But carbon-12 has 6 neutrons and carbon-14 has 8 neutrons. Almost all carbon atoms are carbon-12. This is a stable isotope of carbon. Only a tiny percentage of carbon atoms are carbon-14. Carbon-14 is unstable. Figure 11.16 shows carbon dioxide, which forms in the atmosphere from carbon-14 and oxygen. Neutrons in cosmic rays strike nitrogen atoms in the atmosphere. The nitrogen forms carbon- 14. Carbon in the atmosphere combines with oxygen to form carbon dioxide. Plants take in carbon dioxide during photosynthesis. In this way, carbon-14 enters food chains. Like other unstable isotopes, carbon-14 breaks down, or decays. For carbon-14 decay, each carbon-14 atom loses an alpha particle. It changes to a stable atom of nitrogen-14. This is illustrated in Figure 11.17. The decay of an unstable isotope to a stable element occurs at a constant rate. This rate is different for each isotope pair. The decay rate is measured in a unit called the half-life. The half-life is the time it takes for half of a given amount of an isotope to decay. For example, the half-life of carbon-14 is 5730 years. Imagine that you start out with 100 grams of carbon-14. In 5730 years, half of it decays. This leaves 50 grams of carbon-14. Over the next 5730 years, half of the remaining amount will decay. Now there are 25 grams of carbon-14. How many grams will there be in another 5730 years? Figure 11.18 graphs the rate of decay of carbon-14. The rate of decay of unstable isotopes can be used to estimate the absolute ages of fossils and rocks. This type of dating is called radiometric dating. The best-known method of radiometric dating is carbon-14 dating. A living thing takes in carbon-14 (along with stable carbon-12). As the carbon-14 decays, it is replaced with more carbon-14. After the organism dies, it stops taking in carbon. That includes carbon-14. The carbon-14 that is in its body continues to decay. So the organism contains less and less carbon-14 as time goes on. We can estimate the amount of carbon-14 that has decayed by measuring the amount of carbon-14 to carbon-12. We know how fast carbon-14 decays. With this information, we can tell how long ago the organism died. Carbon-14 has a relatively short half-life. It decays quickly compared to some other unstable isotopes. So carbon- 14 dating is useful for specimens younger than 50,000 years old. Thats a blink of an eye in geologic time. But radiocarbon dating is very useful for more recent events. One important use of radiocarbon is early human sites. Carbon-14 dating is also limited to the remains of once-living things. To date rocks, scientists use other radioactive isotopes. The isotopes in Table 11.1 are used to date igneous rocks. These isotopes have much longer half-lives than carbon- 14. Because they decay more slowly, they can be used to date much older specimens. Which of these isotopes could be used to date a rock that formed half a million years ago? Unstable Isotope Decays to At a Half-Life of (years) Potassium-40 Uranium-235 Uranium-238 Argon-40 Lead-207 Lead-206 1.3 billion 700 million 4.5 billion Dates Rocks Aged (years old) 100 thousand - 1 billion 1 million - 4.5 billion 1 million - 4.5 billion
Example Output:
How much percent of the parent isotope remains after 2 half-lives?