instruction:
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."
question:
Background Paragraph: River deltas form when a river carrying sediment reaches either (1) a body of water, such as a lake, ocean, or reservoir, (2) another river that cannot remove the sediment quickly enough to stop delta formation, or (3) an inland region where the water spreads out and deposits sediments. The tidal currents also cannot be too strong, as sediment would wash out into the water body faster than the river deposits it. The river must carry enough sediment to layer into deltas over time. The river's velocity decreases rapidly, causing it to deposit the majority, if not all, of its load. This alluvium builds up to form the river delta.[7] When the flow enters the standing water, it is no longer confined to its channel and expands in width. This flow expansion results in a decrease in the flow velocity, which diminishes the ability of the flow to transport sediment. As a result, sediment drops out of the flow and deposits. Over time, this single channel builds a deltaic lobe (such as the bird's-foot of the Mississippi or Ural river deltas), pushing its mouth into the standing water. As the deltaic lobe advances, the gradient of the river channel becomes lower because the river channel is longer but has the same change in elevation (see slope). 
Story: The Danube and Volga rivers both form large deltas, but the Danube river delta is larger and grows faster every year.
answer:
Which river carries fewer sediments?


question:
Background Paragraph: Alpine tundra occurs at high enough altitude at any latitude. Portions of montane grasslands and shrublands ecoregions worldwide include alpine tundra. Large regions of alpine tundra occur in the North American Cordillera, the Alps and Pyrenees of Europe, the Himalaya and Karakoram of Asia, the Andes of South America, and the Eastern Rift mountains of Africa.Alpine tundra occupies high-mountain summits, slopes, and ridges above timberline. Aspect plays a role as well; the treeline often occurs at higher elevations on warmer equator-facing slopes. Because the alpine zone is present only on mountains, much of the landscape is rugged and broken, with rocky, snowcapped peaks, cliffs, and talus slopes, but also contains areas of gently rolling to almost flat topography.Averaging over many locations and local microclimates, the treeline rises 75 metres (245 ft) when moving 1 degree south from 70 to 50°N, and 130 metres (430 ft) per degree from 50 to 30°N. Between 30°N and 20°S, the treeline is roughly constant, between 3,500 and 4,000 metres (11,500 and 13,100 ft). 
Story: Two countries from the same continent have very different climates. Icelandia, located at 70°N latitude, and Uganda, situated just south of 30°N, Icelandia was mostly flat, had a few mountains under 1,000 ft, but Uganda had a mountain range with peaks just under 3,000 ft.
answer:
Which country had a higher timberline?


question:
Background Paragraph: Natural resources include energy, minerals and other materials. Natural resources may be renewable or non-renewable. Non-renewable resources cannot be replaced. When they're gone, they're gone. Renewable resources can be replaced. They can supply human activities forever. Fossil fuels are crucial for modern human society. Fossil fuels are essential for transportation, industry and agriculture. Renewable energy resources tend to be clean. They emit fewer pollutants and greenhouse gases than fossil fuels. Renewable resources often have other problems. They are more costly and less efficient than fossil fuels. Still, they have many advantages. Research is going into developing renewable resources. Conservation is the best way to increase resource availability. Anyone can conserve! You and your family can. Society can. The world can. Just reduce, reuse, recycle. 
Story: Germany took steps to increase the use of renewable natural resources. Today, they are the leader in using renewable resources. Most of their energy requirements are met with renewable natural resources. But it's not the case with nearby Russia. Russia has been heavily depended on non-renewable natural resources. With the discovery of huge gas and oil reserves there is no sign that situation would change in Russia any time soon.
answer:

Which country would emit less pollutants, Germany or Russia?