Given a question and a context passage, generate the answer having the word or phrase from the context passage. Here, the answer should be a shortest continous span from the passage.

Example Input: Context: In the Caucasus region of Russia, nearly 50 out of every 100,000 people live to celebrate their 100th birthday, and many don't stop at 100! By comparison, in America only 3 people in 100,000 reach 100. But these Russian old people aren't alone. The Pakistanis, who live high in the Himalaya Mountains, and the Ecuadorans of the Andes Mountains seem to share the secret of long life, too. These people remain healthy in body and spirit despite the passage of time. While many older persons in industrial societies become weak and ill in their 60s and 70s, some Caucasians aged 100 to 140, work in the fields beside their great-great-grandchildren. Even the idea of aging is foreign to them. When asked "at what age does youth end?"most of these old people had no answer. Several replied, "Well, perhaps at age 80." What accounts for this ability to survive to such old age, and to survive so well?First of all, hard physical work is a way of life for all of these long-lived people. They begin their long days of physical labor as children and never seem to stop. For example, Mr . Rustam Mamedov is 142 years of age. His wife is 116 years old. They have been married for 90 years. Mr. Mamedov has no intention of retiring from his life as a farmer. "Why?What else would I do?"he asks. All these people get healthful rewards from the environment in which they work. They all come from mountainous regions. They live and work at elevations of 1,660 to 1,000 meters above sea level. The air has less oxygen and is pollution-free. This reduced-oxygen environment makes the heart and blood vessel system stronger. Another factor that may contribute to the good health of these people is their isolation. To a great extent, they are separated from the pressures and worries of industrial society. Inherited factors also play some role. Most of the longest-lived people had parents and grandparents who also reached very old ages. Good family genes may, therefore, be one factor in living longer.
Question: What is the main way of life for all of these long-lived people?
Example Output: hard physical work.

Example Input: Context: The All-Russia People's Front (Russian: ), known by its Russian initialism ONF, is a movement in Russia started in 2011 by then-Prime Minister of Russia Vladimir Putin to provide United Russia with ''new ideas, new suggestions and new faces''.
Question: Who led All-Russia People's Front?
Example Output: vladimir putin

Example Input: Context: Freshwater below Earths surface is called groundwater. The water infiltrates, or seeps down into, the ground from the surface. How does this happen? And where does the water go? Water infiltrates the ground because soil and rock are porous. Between the grains are pores, or tiny holes. Since water can move through this rock it is permeable. Eventually, the water reaches a layer of rock that is not porous and so is impermeable. Water stops moving downward when it reaches this layer of rock. Look at the diagram in Figure 13.11. It shows two layers of porous rock. The top layer is not saturated; it is not full of water. The next layer is saturated. The water in this layer has nowhere else to go. It cannot seep any deeper into the ground because the rock below it is impermeable. The top of the saturated rock layer in Figure 13.11 is called the water table. The water table isnt like a real table. It doesnt remain firmly in one place. Instead, it rises or falls, depending on how much water seeps down from the surface. The water table is higher when there is a lot of rain and lower when the weather is dry. An underground layer of rock that is saturated with groundwater is called an aquifer. A diagram of an aquifer is shown in Figure 13.12. Aquifers are generally found in porous rock, such as sandstone. Water infiltrates the aquifer from the surface. The water that enters the aquifer is called recharge. Most land areas have aquifers beneath them. Many aquifers are used by people for freshwater. The closer to the surface an aquifer is, the easier it is to get the water. However, an aquifer close to the surface is also more likely to become polluted. Pollutants can seep down through porous rock in recharge water. An aquifer that is used by people may not be recharged as quickly as its water is removed. The water table may lower and the aquifer may even run dry. If this happens, the ground above the aquifer may sink. This is likely to damage any homes or other structures built above the aquifer. One of the biggest aquifers in the world is the Ogallala aquifer. As you can see from Figure 13.13, this aquifer lies beneath parts of eight U.S. states. It covers a total area of 451,000 square kilometers (174,000 square miles). In some places, it is less than a meter deep. In other places, it is hundreds of meters deep. The Ogallala aquifer is an important source of freshwater in the American Midwest. This is a major farming area, and much of the water is used to irrigate crops. The water in this aquifer is being used up ten times faster than it is recharged. If this continues, what might happen to the Ogallala aquifer? The top of an aquifer may be high enough in some places to meet the surface of the ground. This often happens on a slope. The water flows out of the ground and creates a spring. A spring may be just a tiny trickle, or it may be a big gush of water. One of the largest springs in the world is Big Spring in Missouri, seen in Figure 13.14. Water flowing out of the ground at a spring may flow downhill and enter a stream. Thats what happens to the water that flows out of Big Spring in Missouri. If the water from a spring cant flow downhill, it may spread out to form a pond or lake instead. Lake George in New York State, which is pictured in Figure 13.15, is a spring-fed lake. The lake basin was carved by a glacier. Some springs have water that contains minerals. Groundwater dissolves minerals out of the rock as it seeps through the pores. The water in some springs is hot because it is heated by hot magma. Many hot springs are also mineral springs. Thats because hot water can dissolve more minerals than cold water. Grand Prismatic Spring, shown in Figure 13.16, is a hot mineral spring. Dissolved minerals give its water a bright blue color. The edge of the spring is
Question: Water in a spring comes from a
Example Output:
layer of rock.