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.

Q: Background Paragraph: Soil formation, or pedogenesis, is the combined effect of physical, chemical, biological and anthropogenic processes working on soil parent material. Soil is said to be formed when organic matter has accumulated and colloids are washed downward, leaving deposits of clay, humus, iron oxide, carbonate, and gypsum, producing a distinct layer called the B horizon. This is a somewhat arbitrary definition as mixtures of sand, silt, clay and humus will support biological and agricultural activity before that time. These constituents are moved from one level to another by water and animal activity. As a result, layers (horizons) form in the soil profile. The alteration and movement of materials within a soil causes the formation of distinctive soil horizons. However, more recent definitions of soil embrace soils without any organic matter, such as those regoliths that formed on Mars and analogous conditions in planet Earth deserts.An example of the development of a soil would begin with the weathering of lava flow bedrock, which would produce the purely mineral-based parent material from which the soil texture forms. Soil development would proceed most rapidly from bare rock of recent flows in a warm climate, under heavy and frequent rainfall. Under such conditions, plants (in a first stage nitrogen-fixing lichens and cyanobacteria then epilithic higher plants) become established very quickly on basaltic lava, even though there is very little organic material. The plants are supported by the porous rock as it is filled with nutrient-bearing water that carries minerals dissolved from the rocks. Crevasses and pockets, local topography of the rocks, would hold fine materials and harbour plant roots. The developing plant roots are associated with mineral-weathering mycorrhizal fungi that assist in breaking up the porous lava, and by these means organic matter and a finer mineral soil accumulate with time. Such initial stages of soil development have been described on volcanoes, inselbergs, and glacial moraines. 
Story: Ben and Jerry studied agricultural sciences. Ben was specialized in pedology and pedogenesis, while Jerry specialized in entomology and phytopathology. 
Question: Which person learned more about deposits of humus?

A: Ben.
****
Q: Background Paragraph: A baby is born with zones of cartilage in its bones that allow growth of the bones. These areas, called growth plates , allow the bones to grow longer as the child grows. By the time the child reaches an age of about 18 to 25 years, all of the cartilage in the growth plate has been replaced by bone. This stops the bone from growing any longer. Even though bones stop growing in length in early adulthood, they can continue to increase in thickness throughout life. This thickening occurs in response to strain from increased muscle activity and from weight-lifting exercises. 
Story: Two brothers, Tom, aged 26, and Paul, aged 16 were into sports. Tom started weight-lifting to gain more muscle mass. Three years later he was 20-25 lbs. heavier. Paul started track and field, he liked running. 
Question: Which brother had thicker bones after three years?

A: Tom.
****
Q: Background Paragraph: New species develop naturally through the process of natural selection . Due to natural selection, organisms with traits that better enable them to adapt to their environment will tend to survive and reproduce in greater numbers. Natural selection causes beneficial heritable traits to become more common in a population and unfavorable heritable traits to become less common. For example, a giraffe’s neck is beneficial because it allows the giraffe to reach leaves high in trees. Natural selection caused this beneficial trait to become more common than short necks. 
Story: Mike lives in a cold mid-western city, where there is not much predator prey interaction. Mike noticed that in his city some squirrels have darker coat, while others have lighter coat. He also knew that darker coats are more suitable in cold environment with less predator prey interaction. He started thinking why the squirrels developed different coat colors. 
Question: Which squirrels would most likely reproduce in smaller numbers, lighter or darker?

A:
lighter.
****