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: 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: In the Kenya-Tanzania border Kenyan grassland gradually merges into Tanzanian forest. Though they had similar soil to start with millions of years ago, today they are two different habitats. At present, Kenya has one of the largest contiguous grassland in Africa. On the other hand, Tanzania boasts one of the largest forest cover in Africa. 
Question: Which place would have thinner "A horizon", Kenya or Tanzania?
answer:
Tanzania.


question:
Background Paragraph: A wood-decay fungus is any species of fungus that digests moist wood, causing it to rot. Some species of wood-decay fungi attack dead wood, such as brown rot, and some, such as Armillaria (honey fungus), are parasitic and colonize living trees. Excessive moisture above the fibre saturation point in wood is required for fungal colonization and proliferation.[1] Fungi that not only grow on wood but permeate its fibrous structure and actually cause decay, are called lignicolous fungi. In nature, this process causes the breakdown of complex molecules and leads to the return of nutrients to the soil.[2] Various lignicolous fungi consume wood in various ways; for example, some attack the carbohydrates in wood and some others decay lignin. The rate of decay of wooden materials in various climates can be estimated by empirical models.[3]. 
Story: The mycologist wanted to move to a rural area, to further his research, and found these two villages situated 10 miles from each other. The interesting fact about these villages was that while both villages had a forest nearby, one presented more signs of water saturation than the other, so that the rate of decay in wood was greater in Peak Forest. More fungi were present in Peak Forest. The Valley Forest was dryer, although the rain amounts were similar, partially because of a drainage system composed of ditches, that were dug by the locals. The rate of wood decay continued to increase in the Peak Forest, while being significantly reduced in the Valley Forest. 
Question: Was the breakdown of complex molecules lesser or greater in Valley Forest?
answer:
lesser.


question:
Background Paragraph: If only 1.0 mL of 0.10 M hydrochloric acid is added to 1.0 L of pure water the pH drops drastically from 7.0 to 4.0. This is a 1000-fold increase in the acidity of the solution. For many purposes, it is desirable to have a solution which is capable of resisting such large changes in pH when relatively small amounts of acid or base are added to them. Such a solution is called a buffer. A buffer is a solution of a weak acid or a base and its salt. Both components must be present for the system to act as a buffer to resist changes in pH. Commercial buffer solutions, which have a wide variety of pH values, can be obtained. 
Story: John is a scientist in a large pharmaceutical company. He devices many useful products using his knowledge of chemistry. Today, he has four solutions in front of him, solution A, solution B, solution C, and solution D. Solution A is a buffer, but solution B is not a buffer. Solution C is acidic, but solution D is not acidic. He needs to figure out what each solution does. 
Question: Which solution has a weak acid or a base and its salt, solution A or solution B?
answer:

solution A.