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.

[EX Q]: Background Paragraph: The example of someone having a positive experience with a drug is easy to see how drug dependence and the law of effect works. The tolerance for a drug goes up as one continues to use it after having a positive experience with a certain amount the first time.[38] It will take more and more to get that same feeling. This is when the controlled substance in an experiment would have to be modified and the experiment would really begin. The law of work for psychologist B. F. Skinner almost half a century later on the principles of operant conditioning, "a learning process by which the effect, or consequence, of a response influences the future rate of production of that response.[39]. 
Story: The Blow Brigade met to discuss their experiences. They all said they always had a great experience using blow and used the same amount each time. They told how many times they used blow. Gloria used it 20 times, Evelyn used it 25 times, Jean used it 37 times, Cheryl used it 48 times, Mildred used it 56 times, Katherine used it 64 times, and Joan used it 70 times. 
Question: Who has a higher tolerance for blow: Mildred or Joan?
[EX A]: Joan.

[EX Q]: Background Paragraph: During Amniocentesis a small amount of amniotic fluid, which contains fetal cells, is extracted from the amnion or amniotic sac surrounding a developing fetus, and the fetal DNA is examined for genetic abnormalities. Amniocentesis is not performed for every pregnancy, but is generally done when an increased risk of genetic defects in the fetus is indicated, by mother's age (over 35 years is common), family history of genetic defects, or other factors. 
Story: David is a doctor with the city hospital. Today, he is seeing four patients, patient A, patient B, patient C, and patient D. All four patients are expectant mothers. Moreover, patient A is over thirty five years old, but patient B is under thirty five years old. Patient C has family history of genetic disorder, but patient D does not have any family history of genetic disorder. David needs to prescribe appropriate treatment according to each patient's condition. 
Question: Would patient A be less or more at risk of genetic defects in the fetus than patient B?
[EX A]: more.

[EX Q]: Background Paragraph: Besides anthropogenic productivity of the land, the biodiversity of degraded land also declines, as previously mentioned.[12] With less biodiversity, this ecosystem is less adaptable to when disasters strike it[11][8] It has a smaller available food supply, in terms of plants, for animals, who then may die out or more likely may relocate. Proof of this decline is that presently 15-20% of Tibetan Plateau species are now considered endangered; and now because of this animal and plant absence, the soil quality of these degraded lands is very poor.[1] It does not hold the necessary nutrients, such as water, nitrogen, and carbon, essential to either supporting life or inviting life back to that land.[6] As a result of such carbon and nitrogen loss in the Tibetan Plateau, $8,033/ha and $13,315/ha were respectively lost in economic terms. Soils are further weakened by dust storms whose frequency increases because of degradation.[11][4] Erosion of soil becomes a bigger problem, since no longer are there as many plants to anchor in the soil. In the northern Chinese province alone, 400 million are affected every year with an associated 54 billion yuan of annual economic loss due to grassland degradation. 
Story: The southern province was exposed to intensive grazing for many years , and now soil quality is poor and dust storms are present. The northern province has more fertile soil, more trees. 
Question: Which province experiences more carbon loss?
[EX A]:
southern.