TASK DEFINITION: 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.
PROBLEM: Background Paragraph: The stronger of two acids will have a higher Ka than the weaker acid; the ratio of hydrogen ions to acid will be higher for the stronger acid as the stronger acid has a greater tendency to lose its proton. Because the range of possible values for Ka spans many orders of magnitude, a more manageable constant, pKa is more frequently used, where pKa = log10 Ka. Stronger acids have a smaller pKa than weaker acids. Experimentally determined pKa at 25 C in aqueous solution are often quoted in textbooks and reference material.
Story: Jacob and Thomas were conducting an experiment in a chemistry class. The goal of the experiment was to identify the strength of unknown acids by examining the products formed in a chemical reaction. After they completed the experiment, Jacob concluded that he was given a strong acid, while Thomas concluded that he was given a weak acid.
Question: Which person's acid, Jacob's or Thomas's, will have a larger pKa?

SOLUTION: Thomas's.

PROBLEM: Background Paragraph: The earliest members of the human species evolved around 200,000 years ago in Africa. Early humans lived in small populations of nomadic hunters and gatherers. Human beings remained in Africa until about 40,000 years ago. After that, they spread throughout Europe, Asia, and Australia. By 10,000 years ago, the first human beings colonized the Americas. During this long period of time, the total number of human beings increased very slowly. Birth rates were fairly high but so were death rates, producing low rates of population growth.
Story: Archaeologists studied data about human settlements. One was 100,000 years old called village R, and the other one was about 9,000 years old called village N. The older settlement was located in Africa, the other one wasn't.
Question: Which village had fewer people that were hunters?

SOLUTION: village N.

PROBLEM: Background Paragraph: There are many examples in the chemical world of changes in entropy. Phase transitions are one obvious example. When a substance makes a transition from the liquid state to the gaseous state, the particles have many more possible arrangements, because they are no longer confined to a specified volume in which they are close to each other; gas particles can move freely throughout their container. Vaporization represents an increase in entropy. In the opposite direction, a liquid loses entropy when it freezes to a solid. Because solids have very ordered structures, there are fewer possible arrangements of particles that would result in the properties associated with a solid.
Story: Rob was in his chemistry lab, experimenting with different states of matter. He had a liquid substance that he labeled as state A. He then transformed half of the liquid substance to gaseous state. He labeled it as state B. Finally, he froze the remaining half of the liquid to solid state. He labeled it as state C.
Question: Which state has less possible arrangements, state A or state B?

SOLUTION:
state A.