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

Input: Consider Input: Frederik Helstrup Jensen (born 16 March 1993) is a Danish footballer who plays for Helsingborgs IF of the Allsvenskan in Sweden.

Output: What was the name of Frederik Helstrup's team?


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: If the outside environment of a cell is water-based, and the inside of the cell is also mostly water, something has to make sure the cell stays intact in this environment. What would happen if a cell dissolved in water, like sugar does? Obviously, the cell could not survive in such an environment. So something must protect the cell and allow it to survive in its water-based environment. All cells have a barrier around them that separates them from the environment and from other cells. This barrier is called the plasma membrane, or cell membrane. The plasma membrane ( Figure 1.1) is made of a double layer of special lipids, known as phospholipids. The phospholipid is a lipid molecule with a hydrophilic ("water-loving") head and two hydrophobic ("water-hating") tails. Because of the hydrophilic and hydrophobic nature of the phospholipid, the molecule must be arranged in a specific pattern as only certain parts of the molecule can physically be in contact with water. Remember that there is water outside the cell, and the cytoplasm inside the cell is mostly water as well. So the phospholipids are arranged in a double layer (a bilayer) to keep the cell separate from its environment. Lipids do not mix with water (recall that oil is a lipid), so the phospholipid bilayer of the cell membrane acts as a barrier, keeping water out of the cell, and keeping the cytoplasm inside the cell. The cell membrane allows the cell to stay structurally intact in its water-based environment. The function of the plasma membrane is to control what goes in and out of the cell. Some molecules can go through the cell membrane to enter and leave the cell, but some cannot. The cell is therefore not completely permeable. "Permeable" means that anything can cross a barrier. An open door is completely permeable to anything that wants to enter or exit through the door. The plasma membrane is semipermeable, meaning that some things can enter the cell, and some things cannot. The inside of all cells also contain a jelly-like substance called cytosol. Cytosol is composed of water and other molecules, including enzymes, which are proteins that speed up the cells chemical reactions. Everything in the cell sits in the cytosol, like fruit in a jello mold. The term cytoplasm refers to the cytosol and all of the organelles, the specialized compartments of the cell. The cytoplasm does not include the nucleus. As a prokaryotic cell does not have a nucleus, the DNA is in the cytoplasm.


Output: the plasma membrane is made of a double layer of __________.