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.

Ex Input:
Context: Weathering changes solid rock into sediments. Sediments are different sizes of rock particles. Boulders are sedi- ments; so is gravel. At the other end, silt and clay are also sediments. Weathering causes rocks at the Earths surface to change form. The new minerals that form are stable at the Earths surface. It takes a long time for a rock or mountain to weather. But a road can do so much more quickly. If you live in a part of the world that has cold winters, you may only have to wait one year to see a new road start to weather (Figure Mechanical weathering breaks rock into smaller pieces. These smaller pieces are just like the bigger rock; they are just smaller! The rock has broken without changing its composition. The smaller pieces have the same minerals in the same proportions. You could use the expression a chip off the old block to describe mechanical weathering! The main agents of mechanical weathering are water, ice, and wind. Rocks can break apart into smaller pieces in many ways. Ice wedging is common where water goes above and below its freezing point (Figure 9.2). This can happen in winter in the mid-latitudes or in colder climates in summer. Ice wedging is common in mountainous regions. This is how ice wedging works. When liquid water changes into solid ice, it increases in volume. You see this when you fill an ice cube tray with water and put it in the freezer. The ice cubes go to a higher level in the tray than the water. You also may have seen this if you put a can of soda into the freezer so that it cools down quickly. If you leave the can in the freezer too long, the liquid expands so much that it bends or pops the can. (For the record, water is very unusual. Most substances get smaller when they change from a liquid to a solid.) Abrasion is another type of mechanical weathering. With abrasion, one rock bumps against another rock. Gravity causes abrasion as a rock tumbles down a slope. Moving water causes abrasion it moves rocks so that they bump against one another (Figure 9.3). Strong winds cause abrasion by blasting sand against rock surfaces. Finally, the ice in glaciers cause abrasion. Pieces of rock embedded in ice at the bottom of a glacier scrape against the rock below. If you have ever collected beach glass or pebbles from a stream, you have witnessed the work of abrasion. Sometimes biological elements cause mechanical weathering. This can happen slowly. A plants roots grow into a crack in rock. As the roots grow larger, they wedge open the crack. Burrowing animals can also cause weathering. By digging for food or creating a hole to live in the animal may break apart rock. Today, human beings do a lot of mechanical weathering whenever we dig or blast into rock. This is common when we build homes, roads, and subways, or quarry stone for construction or other uses. Mechanical weathering increases the rate of chemical weathering. As rock breaks into smaller pieces, the surface area of the pieces increases. With more surfaces exposed, there are more places for chemical weathering to occur. Lets say you wanted to make some hot chocolate on a cold day. It would be hard to get a big chunk of chocolate to dissolve in your milk or hot water. Maybe you could make hot chocolate from some smaller pieces like chocolate chips, but it is much easier to add a powder to your milk. This is because the smaller the pieces are, the more surface area they have. Smaller pieces dissolve more easily. Chemical weathering is different than mechanical weathering. The minerals in the rock change. The rock changes composition and becomes a different type of rock. Most minerals form at high pressure or high temperatures deep within Earth. But at Earths surface, temperatures and pressures are much lower. Minerals that were stable deeper in the crust are not stable at the surface. Thats why chemical weathering happens. Minerals that formed at higher temperature and pressure change into minerals that are stable at the surface. Chemical weathering is important. It 
 Question: type of weathering that changes the minerals in rock

Ex Output:
chemical weathering


Ex Input:
Context: This article's plot summary may be too long or excessively detailed. Please help improve it by removing unnecessary details and making it more concise. (April 2015) (Learn how and when to remove this template message) Part 1 Alice in Wonderland[edit] The first part opens with Alice helping Mother set the table for tea time. Although thankful for her daughter's help, Mother tells Alice that she is still not grown-up enough to join the adults at tea. Alice goes outside to see her sister (played by Natalie's real-life older sister Sharee Gregory), but gets bored of reading a book with no pictures. Her sister tells her that she will understand when she grows up, but Alice thinks she is already grown up (after all, she's seven and a half). While playing with her kitten, Dinah, the White Rabbit comes running by, saying he's late. Wondering where he is going, Alice follows him and tumbles into his rabbit hole. (Unlike the book and most movie versions, this rabbit hole appears to be dark and spooky.) Alice finds herself in a hall with many doors, and all of them locked. On a table is a key which she can use to open one small door. Yet the door is far too small to even fit her head in. A small bottle appears labeled "Drink Me". She comes back to the table and puts it to her lips. Doing this, she shrinks to the right size for the door, but can no longer reach the key to open it. She then sees a small box which she opens and finds a little cake with the words "Eat Me" on it. She then grows to over nine feet tall. Frustrated with the thought of being stuck at nine feet tall, she begins to cry. Her tears fall on the floor and flow under the cracks. The White Rabbit appears, but frightened of the giant Alice runs away dropping his fan and gloves. Using the fan makes Alice shrink again to a size small enough to crawl into one of the cracks, which takes her diving in her pool of tears. While swimming in the pool of her own tears, she meets The Lory Bird, The Dodo Bird and the Mouse, who tells her why he hates dogs and cats ("I Hate Dogs and Cats"). Alice catches up with the White Rabbit. He mistakes Alice for his housemaid Mary Ann and orders her to go get his fan and gloves from his house. While searching his house, Alice curiously finds another "Drink Me" bottle and it makes her sprout to her full nine-foot character once again. Angry at Alice, the rabbit and his friend Pat the Pig try to employ Bill the Lizard to remove Alice by pulling her out the chimney. Having tried unsuccessfully the White Rabbit and Pat begin throwing berries at her which turn into little cakes. She eats one and shrinks to back to size. After running away she meets the Caterpillar who tells her the story ("You are Old, Father William"). She then goes to the house of The Duchess and her pepper loving, plate throwing cook. Finding the house too violent and hateful, she takes the Duchess' baby away, but then it turns into a pig. She meets the Cheshire Cat, who tells her that she can't get out of this land ("There's No Way Home"). He then gives her directions to see either the March Hare or the Mad Hatter, but warns Alice that they, along with everyone else, are mad. Alice finds the Mad Hatter, March Hare, and the Dormouse having an outdoor tea party, and sits down to join them. As tea time entertainment the Mad Hatter, who does not like her version of twinkle, twinkle little star, sings Alice a song of his own ("Laugh"). Upset by the rudeness of the Mad Tea Party, Alice runs off back on her quest for the White Rabbit, and meets a baby fawn in the forest, the only normal thing she's seen so 
 Question: Who plays a prank on the queen?

Ex Output:
the deck of cards


Ex Input:
Context: FreeBSD is a free Unix-like operating system descended from Research Unix via the Berkeley Software Distribution (BSD). 
 Question: The FreeBSD is based upon what?

Ex Output:

berkeley software distribution