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: Hemophilia is the name of a group of hereditary diseases that affect the body's ability to control blood clotting. Hemophilia is caused by a lack of clotting factors in the blood. Clotting factors are normally released by platelets. Since people with hemophilia cannot produce clots, any cut can put a person at risk of bleeding to death. The risk of internal bleeding is also increased in hemophilia, especially into muscles and joints. This disease affected the royal families of Europe. 
Story: Czar Nicholas was the last Romanov who ruled Russia. Al along he was in good health, but that was not the case with his son Prince Alexei. While Nicholas was free from hemophilia, a disease that devastated European royal families, Alexei was born with hemophilia. Many suggest this situation made some opportunists to take advantage of the Czar. 
Question: Who would have more risk of bleeding to death, Nicholas or Alexei?
[EX A]: Alexei.

[EX Q]: Background Paragraph: A person with a serious brain injury usually suffers permanent brain damage. These brain injuries usually occur when an external mechanical force, such as a violent blow or jolt to the head or body, causes brain dysfunction. An object penetrating the skull, such as a bullet or a shattered piece of the skull, also can cause traumatic brain injury. As a result, the person may have trouble talking or controlling body movements. Symptoms depend on what part of the brain was injured. Serious brain injuries can also cause personality changes and problems with mental abilities such as memory. Medicines, counseling, and other treatments may help people with serious brain injuries recover from, or at least learn to cope with, their disabilities. 
Story: Tammy and Rob rode a tandem bike down the hill. They hit a large rock and fell. Tammy wound up in the hospital and was diagnosed with a serious brain injury. Rob suffered only a mild concussion. 
Question: Which person had fewer problems with mental abilities?
[EX A]: Rob.

[EX Q]: Background Paragraph: In grassland, much of the organic matter added to the soil is from the deep, fibrous, grass root systems. By contrast, tree leaves falling on the forest floor are the principal source of soil organic matter in the forest. Another difference is the frequent occurrence in the grasslands of fires that destroy large amounts of aboveground material but stimulate even greater contributions from roots. Also, the much greater acidity under any forests inhibits the action of certain soil organisms that otherwise would mix much of the surface litter into the mineral soil. As a result, the soils under grasslands generally develop a thicker A horizon with a deeper distribution of organic matter than in comparable soils under forests, which characteristically store most of their organic matter in the forest floor (O horizon) and thin A horizon. 
Story: Two pedologists studied different types of soil. Yun studied forest soils, while Jian studied grassland soil. They were both very surprised with they findings. 
Question: Which scientist read more about deep, fibrous, grass root systems?
[EX A]:
Jian.