You are given a background paragraph that describes one or more causal or qualitative relationships such as a relationship in economics or a scientific law and a story that makes use of the concepts or the relationship described in the provided paragraph. You need to come up with a question about the story that requires an understanding of the relationship described in the background paragraph. The generated question should not be answerable without both the background and story. Write a question about the story that requires a relationship in the background paragraph to answer. Check whether your question requires both the background paragraph and the story to answer. If your question can be answered by only one of these, try to rewrite your question so that it requires both. Note that "flipping" a word in the question can give rise to a new question where the answer will be different from the original question. Often, "flipping" a word gives rise to flipping the direction of the relationship, for example, from "increase" to "decrease."

[Q]: Background Paragraph: Depleted soils can be protected from soil erosion by groundcover plants such as naturally growing grasses in agroforestry systems. These help to stabilise the soil as they increase cover compared to short-cycle cropping systems. Soil cover is a crucial factor in preventing erosion. Cleaner water through reduced nutrient and soil surface runoff can be a further advantage of agroforestry. The runoff can be reduced by decreasing its velocity and increasing infiltration into the soil. Compared to row-cropped fields nutrient uptake can be higher and reduce nutrient loss into streams.Further advantages concerning plant growth:. 
Story: Dan, a renowned pedologist, visited two farms near his home town. Grape farm had depleted soils and a low crop production, while Fruit farm, having parcels with depleted soils in the past, established an agroforestry system starting a decade ago which helped stabilize soil and increase production.
[A]: Which farm contributed to reducing nutrient runoff?


[Q]: Background Paragraph: Around 5.4 billion years from now, the core of the Sun will become hot enough to trigger hydrogen fusion in its surrounding shell. This will cause the outer layers of the star to expand greatly, and the star will enter a phase of its life in which it is called a red giant. Within 7.5 billion years, the Sun will have expanded to a radius of 1.2 AU—256 times its current size. At the tip of the red giant branch, as a result of the vastly increased surface area, the Sun's surface will be much cooler (about 2600 K) than now and its luminosity much higher—up to 2,700 current solar luminosities. For part of its red giant life, the Sun will have a strong stellar wind that will carry away around 33% of its mass. During these times, it is possible that Saturn's moon Titan could achieve surface temperatures necessary to support life.As the Sun expands, it will swallow the planets Mercury and Venus. Earth's fate is less clear; although the Sun will envelop Earth's current orbit, the star's loss of mass (and thus weaker gravity) will cause the planets' orbits to move farther out. If it were only for this, Venus and Earth would probably escape incineration, but a 2008 study suggests that Earth will likely be swallowed up as a result of tidal interactions with the Sun's weakly bound outer envelope.Gradually, the hydrogen burning in the shell around the solar core will increase the mass of the core until it reaches about 45% of the present solar mass. At this point the density and temperature will become so high that the fusion of helium into carbon will begin, leading to a helium flash; the Sun will shrink from around 250 to 11 times its present (main-sequence) radius. Consequently, its luminosity will decrease from around 3,000 to 54 times its current level, and its surface temperature will increase to about 4770 K. The Sun will become a horizontal giant, burning helium in its core in a stable fashion much like it burns hydrogen today. The helium-fusing stage will last only 100 million years. Eventually, it will have to again resort to the reserves of hydrogen and helium in its outer layers and will expand a second time, turning into what is known as an asymptotic giant. Here the luminosity of the Sun will increase again, reaching about 2,090 present luminosities, and it will cool to about 3500 K. This phase lasts about 30 million years, after which, over the course of a further 100,000 years, the Sun's remaining outer layers will fall away, ejecting a vast stream of matter into space and forming a halo known (misleadingly) as a planetary nebula. The ejected material will contain the helium and carbon produced by the Sun's nuclear reactions, continuing the enrichment of the interstellar medium with heavy elements for future generations of stars. 
Story: Keith was playing a simulation game. In the game he could travel around the Sun in the future. He started the game in 
present time, which was denoted as time A. Then he traveled 5.4 billion years into the future, which was denoted as time B. Finally, he reached 7.5 billion years into the future, which was denoted as time C. He was amazed to find how the Sun would change over time.
[A]: When would the Sun be brighter, time A or time C?


[Q]: Background Paragraph: The water cycle involves the exchange of energy, which leads to temperature changes. When water evaporates, it takes up energy from its surroundings and cools the environment. When it condenses, it releases energy and warms the environment. These heat exchanges influence climate. 
Story: The community around Lake Superior experienced a crazy weather week. On Sunday, 4 inches of Lake Superior evaporated. On Monday, 3 inches of Lake Superior evaporated. On Tuesday, 2 inches of Lake Superior evaporated. On Wednesday, Thursday, Friday, and Saturday, there was condensation all day.
[A]:
Which day did the environment in the community have a higher cooling: Friday or Sunday?