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 lungs of mammals are unique in having alveoli . These are tiny, sac-like structures. Each alveolus is surrounded by a network of very small blood vessels (see Figure below ). Because there are millions of alveoli in each lung, they greatly increase the surface area for gas exchange between the lungs and bloodstream. Human lungs, for example, contain about 300 million alveoli. They give the lungs a total surface area for gas exchange of up to 90 square meters (968 square feet). That’s about as much surface area as one side of a volleyball court!. 
Story: David is investigating the breathing process of different organisms. He found that humans have alveoli to help them with gas exchange. He got curious about other organisms that do not have alveoli. To compare these two groups he labeled organisms with alveoli as group A and organisms without alveoli as group B. 
Question: Would group A have greater or smaller gas exchange than group B?

SOLUTION: greater.

PROBLEM: Background Paragraph: Baker's yeast is the common name for the strains of yeast commonly used in baking bread and bakery products, serving as a leavening agent which causes the bread to rise (expand and become lighter and softer) by converting the fermentable sugars present in the dough into carbon dioxide and ethanol. Baker's yeast is of the species Saccharomyces cerevisiae,[1] and is the same species (but a different strain) as the kind commonly used in alcoholic fermentation, which is called brewer's yeast.[2] Baker's yeast is also a single-cell microorganism found on and around the human body. 
Story: Ken is a microbiologist. He got two samples of yeasts, yeast A and yeast B, from two different businesses. Yeast A is used in a bakery, and yeast B is used in a brewery. He has to decide the characteristics of each 
yeast sample for further study.
Interestingly, despite all his curiosity, Ken doesn't like any yeast to be around him. 
Question: If Ken wants a dough sample to expand, which yeast should he use, yeast A or yeast B?

SOLUTION: yeast A.

PROBLEM: Background Paragraph: When soil is flooded, hypoxia develops, as soil microorganisms consume oxygen faster than diffusion occurs. The presence of hypoxic soils is one of the defining characteristics of wetlands. Many wetland plants possess aerenchyma, and in some, such as water-lilies, there is mass flow of atmospheric air through leaves and rhizomes. There are many other chemical consequences of hypoxia. For example, nitrification is inhibited as low oxygen occurs and toxic compounds are formed, as anaerobic bacteria use nitrate, manganese, and sulfate as alternative electron acceptors. The reduction-oxidation potential of the rhizhosphere decreases and metal ions such as iron and manganese precipitate. Aerenchyma is a modification of the parenchyma. 
Story: John is a soil scientist. He has been studying the lands near Mississippi delta. He noticed cases of hypoxia in that are. He labeled that study as case A. To compare that to other areas he visited Arizona. There he didn't see any occurrence of hypoxia. He labeled that case as case B. 
Question: Would case B see less or more oxygen in the soil due to microorganism activities than case A?

SOLUTION:
more.