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 are also given a question about the story that requires an understanding of the relationship described in the background paragraph and the story. You need to come up with an answer to the given question; the answer will be a span from either the question or the story. In order to correctly answer the given question, you need to understand the relationship mentioned in the background paragraph and should be able to use it to understand that in the story. Your answer can not consist of any word that is not mentioned in any of these: the background paragraph, the story, or the question. You can directly copy and paste a span from the story or the question while answering the given question.

[EX 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: Two neighboring farms both had depleted soils due to intensive agricultural practices for decades. Apple far decided to start an agroforestry system and other methods to protect their depleted soils, while Pear farm did nothing and had big losses the following years.
Question: Which farm didn't reduce the runoff?
[EX A]: Pear.

[EX Q]: Background Paragraph: Groundwater salinization compromises buffering properties. Vegetation clearance, along with irrigation, causes serious issues. Irrigation increases the water table and mobilizes salts, and vegetation clearance allows it to come in contact with water habitats and vegetation. This stresses species not adapted to high salinity. High levels of salinity reduces water uptake in plants, by causing stomatal closure, reducing photosynthesis. Forests undergo decline in areas of high salinity and shallow groundwater depths because these conditions make them more susceptible to droughts. Forests undergo decline in areas of high salinity and shallow groundwater depths making them more susceptible to droughts.
Story: Two villages were situated on different sides of the hill. Each village has its own approach to agriculture. East village decided to clear the land, by felling many trees and bushes, and set up a vast irrigation system. West village too a more natural approach to food production and applied the edible forest method, and all the permaculture principles over the years.
Question: Which village had more areas of shallow groundwater?
[EX A]: East.

[EX Q]: Background Paragraph: Marine pollution is a generic term for the entry into the ocean of potentially hazardous chemicals or particles. The biggest culprits are rivers and with them many agriculture fertilizer chemicals as well as livestock and human waste. The excess of oxygen-depleting chemicals leads to hypoxia and the creation of a dead zone.Marine debris, which is also known as marine litter, describes human-created waste floating in a body of water. Oceanic debris tends to accumulate at the center of gyres and coastlines, frequently washing aground where it is known as beach litter.
Story: Bird city had may economic ties with Pine city. Pine city was located in the mountains, and was inhabited by nature lovers and people that protected the environment. Bird city was situated on the banks of a large river flowing into the sea. They relied mostly on conventional agriculture and used fertilizer for their crops.
Question: Which city contributed more to marine pollution?
[EX A]:
Bird.