instruction:
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.
question:
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?
answer:
the sun


question:
Context: The 1988 Dungeons & Dragons role-playing game module Ruins of Adventure was produced using the same adventure scenario as Pool of Radiance, using the same plot, background, setting, and many of the same characters as the computer game. 
 Question: The Pool of Radiance is based upon what?
answer:
ruins of adventure


question:
Context: Learn to Communicate with Others Talking to Teachers--Teachers are just people behind the desk, living breathing human beings. And they will probably be friendly to people who talk nicely to them. Teachers also seem to get along better with children who take schoolwork seriously and prepare for class. And, just like any other human being, teachers like to be appreciated. The next time your teacher helps you solve a math problem or figure out a science project, say thank you with a smile. Talking to Parents--Parents can be very supportive if their children ask for help. If you think there's something your parents can do to help you feel more comfortable around people, then ask them. Very often, parents want very much to help, but really don't know what to do. Pick a quiet time of the day and ask to talk. Tell them how you feel. Maybe they had the same trouble when they were kids. Talking to Strangers--This is always a tough one. How do you deal with a neighbor, or the mail carrier? That often seems to cause arguments between kids and parents. The answer to these questions will vary from kid to kid, from parent to parent because all cultures are different. Some folks live in small towns where a hello to everyone is ok. Then there are kids who live in the city who may have been taught not to speak to anyone they don't know. If you're having trouble with this and always feel awkward in these kinds of situations, you might want to talk to your parents or a teacher about it. 
 Question: Who does the writer write this passage for?
answer:

kids