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.

Background Paragraph: A mycorrhiza (Greek for "fungus roots") is a symbiotic association between a fungus and the roots of a plant. In a mycorrhizal association, the fungus may colonize the roots of a host plant by either growing directly into the root cells, or by growing around the root cells. This association provides the fungus with relatively constant and direct access to glucose, which the plant produces by photosynthesis. The mycelia of the fungi increase the surface area of the plant’s root system. The larger surface area improves water and mineral nutrient absorption from the soil. 
Story: Fox and Ken were two aspiring horticulturists. Ken studied more about plant pollination, while Fox studied about mycorrhizal fungi. 
Question: Which friend read less about fungi with direct access to glucose?
Ken.

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?
village N.

Background Paragraph: Enzymes increase the rate of chemical reactions by reducing the amount of activation energy needed for reactants to start reacting. One way this can happen is modeled in the Figure below . Enzymes aren’t changed or used up in the reactions they catalyze, so they can be used to speed up the same reaction over and over again. Each enzyme is highly specific for the particular reaction is catalyzes, so enzymes are very effective. A reaction that would take many years to occur without its enzyme might occur in a split second with the enzyme. Enzymes are also very efficient, so waste products rarely form. 
Story: David is a chemist, working for a large pharmaceutical company. He was contemplating on a project that would help perform chemical reactions more efficiently. For that, he conducted two chemical reaction tests, test A and test B. In test A he used enzymes, but in test B he didn't use any enzymes. He now needs to evaluate the  pros and cons of each of the tests. 
Question: Which test would require shorter time, test A or test B?

test A.