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 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.
question:
Background Paragraph: All of these animal behaviors are important. They help the animals get food for energy, make sure their young survive, or ensure that they, themselves, survive. Behaviors that help animals or their young survive, increase the animals' fitness. Animals with higher fitness have a better chance of passing their genes on to the next generation. If genes control behaviors that increase fitness, the behaviors become more common in the species. This occurs through the process of evolution by natural selection.
Story: David is a biologist. He was in the African savanna to study different species. Especially, he was interested in two species, rhinos and impalas. He noticed that in response to constant human encroachment of wildlife habitats, impalas have acquired some behaviors that help them and their young. Rhinos also have acquired some behaviors in response to the same threat. But their behaviors mostly failed them in that aspect.
Question: In which species the behaviors in question would be more common, rhino or impala?
answer:
impala.

question:
Background Paragraph: Plucking, also referred to as quarrying, is a glacial phenomenon that is responsible for the erosion and transportation of individual pieces of bedrock, especially large "joint blocks". This occurs in a type of glacier called a "valley glacier". As a glacier moves down a valley, friction causes the basal ice of the glacier to melt and infiltrate joints (cracks) in the bedrock. The freezing and thawing action of the ice enlarges, widens, or causes further cracks in the bedrock as it changes volume across the ice/water phase transition (a form of hydraulic wedging), gradually loosening the rock between the joints. This produces large pieces of rock called joint blocks. Eventually these joint blocks come loose and become trapped in the glacier.
Story: Rob likes to visit high mountainous locations. Last year he visited the the Alps mountains in Austria. There he saw an unique type of glacier called valley glacier. This year he went further east to visit the Ural mountains in Russia. There he didn't see any valley glacier.
Question: Which mountain would not see erosion of bedrocks?
answer:
Ural.

question:
Background Paragraph: Retinitis is inflammation of the retina in the eye, which can permanently damage the retina and lead to blindness. The retina is the part of your eye that is also known as the "sensing tissue." Retinitis may be caused by a number of different infectious agents. Retinitis, also called Retinitis pigmentosa, has a prevalence of one in every 2,500-7,000 people. This condition is one of the leading causes that leads to blindness in patients in the age range of 2060 years old.
Story: John is comparing his medical record with his father's and son's medical records. John is 40 years old; his father is 70 years old; and his son is 10 years old. It appears that both John and his father has Retinitis. But his son does not have Retinitis.
Question: Whould Retinitis be a leading cause or minor cause of blindness for John's father?
answer:
minor cause.