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.

Q: Context: Earth formed at the same time as the other planets. The history of Earth is part of the history of the Solar System. Earth came together (accreted) from the cloud of dust and gas known as the solar nebula nearly 4.6 billion years ago, the same time the Sun and the rest of the solar system formed. Gravity caused small bodies of rock and metal orbiting the proto-Sun to smash together to create larger bodies. Over time, the planetoids got larger and larger until they became planets. When Earth first came together it was really hot, hot enough to melt the metal elements that it contained. Earth was so hot for three reasons: Gravitational contraction: As small bodies of rock and metal accreted, the planet grew larger and more massive. Gravity within such an enormous body squeezes the material in its interior so hard that the pressure swells. As Earths internal pressure grew, its temperature also rose. Radioactive decay: Radioactive decay releases heat, and early in the planets history there were many ra- dioactive elements with short half lives. These elements long ago decayed into stable materials, but they were responsible for the release of enormous amounts of heat in the beginning. Bombardment: Ancient impact craters found on the Moon and inner planets indicate that asteroid impacts were common in the early solar system. Earth was struck so much in its first 500 million years that the heat was intense. Very few large objects have struck the planet in the past many hundreds of millions of year. When Earth was entirely molten, gravity drew denser elements to the center and lighter elements rose to the surface. The separation of Earth into layers based on density is known as differentiation. The densest material moved to the center to create the planets dense metallic core. Materials that are intermediate in density became part of the mantle (Figure 1.1). Lighter materials accumulated at the surface of the mantle to become the earliest crust. The first crust was probably basaltic, like the oceanic crust is today. Intense heat from the early core drove rapid and vigorous mantle convection so that crust quickly recycled into the mantle. The recycling of basaltic crust was so effective that no remnants of it are found today. There is not much material to let us know about the earliest days of our planet Earth. What there is comes from three sources: (1) zircon crystals, the oldest materials found on Earth, which show that the age of the earliest crust formed at least 4.4 billion years ago; (2) meteorites that date from the beginning of the solar system, to nearly 4.6 billion years ago (Figure 1.2); and (3) lunar rocks, which represent the early days of the Earth-Moon system as far back as 4.5 billion years ago. 
 Question: which is not a reason why earth was molten in its early days?

A: the sun
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Q: Context: As of the 2010 United States Census, there were 1,951,269 people, 715,365 households, and 467,916 families residing in the county. The population density was . There were 840,343 housing units at an average density of . The racial makeup of the county was 60.9% white, 10.5% black or African American, 8.7% Asian, 0.7% Pacific islander, 0.7% American Indian, 13.5% from other races, and 5.1% from two or more races. Those of Hispanic or Latino origin made up 29.1% of the population. In terms of ancestry, 11.7% were Germans, 9.1% were Irish people, 7.6% were English people, 6.3% were Italians, and 2.7% were Americans. 
 Question: Which group from the census is larger: Germans or Americans?

A: germans
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Q: Context: All electromagnetic waves travel at the same speed through empty space. That speed, called the speed of light, is 300 million meters per second (3.0 108 m/s). Nothing else in the universe is known to travel this fast. If you could move that fast, you would be able to travel around Earth 7.5 times in just 1 second! The sun is about 150 million kilometers (93 million miles) from Earth, but it takes electromagnetic radiation only 8 minutes to reach Earth from the sun. Electromagnetic waves travel more slowly through a medium, and their speed may vary from one medium to another. For example, light travels more slowly through water than it does through air (see Figure 21.4). You can learn more about the speed of light at this URL: [Link] Although all electromagnetic waves travel at the same speed, they may differ in their wavelength and frequency. Wavelength and frequency are defined in the same way for electromagnetic waves as they are for mechanical waves. Both properties are illustrated in Figure 21.5. Wavelength is the distance between corresponding points of adjacent waves. Wavelengths of electromagnetic waves range from many kilometers to a tiny fraction of a millimeter. Frequency is the number of waves that pass a fixed point in a given amount of time. Frequencies of electro- magnetic waves range from thousands to trillions of waves per second. Higher frequency waves have greater energy. The speed of a wave is a product of its wavelength and frequency. Because all electromagnetic waves travel at the same speed through space, a wave with a shorter wavelength must have a higher frequency, and vice versa. This relationship is represented by the equation: Speed = Wavelength Frequency The equation for wave speed can be rewritten as: Frequency = Speed Speed or Wavelength = Wavelength Frequency Therefore, if either wavelength or frequency is known, the missing value can be calculated. Consider an electromag- netic wave that has a wavelength of 3 meters. Its speed, like the speed of all electromagnetic waves, is 3.0 108 meters per second. Its frequency can be found by substituting these values into the frequency equation: Frequency = 3.0 108 m/s = 1.0 108 waves/s, or 1.0 108 hertz (Hz) 3.0 m You Try It! Problem: What is the wavelength of an electromagnetic wave that has a frequency of 3.0 108 hertz? For more practice calculating the frequency and wavelength of electromagnetic waves, go to these URLs: 
 Question: distance between corresponding points of adjacent waves

A:
wavelength
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