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.

[Q]: Background Paragraph: Unfortunately, the layer of good ozone is being destroyed by air pollution. The chief culprits are chlorine and bromine gases. They are released in aerosol sprays, coolants, and other products. Loss of ozone has created an ozone hole over Antarctica. Ozone depletion results in higher levels of UV radiation reaching Earth. In humans, this increases skin cancers and eye cataracts. It also disturbs the nitrogen cycle, kills plankton, and disrupts ocean food webs. The total loss of the ozone layer would be devastating to most life. Its rate of loss has slowed with restrictions on pollutants, but it is still at risk. 
Story: Two teams of researchers studied the environment in Antarctica. Team Black studied air pollution and the ozone layer, Team Red studied the water. 
Question: Which team observed higher levels of UV reaching Earth?
[A]: Black.


[Q]: Background Paragraph: For example, a radioactive isotope of iodine (I-131) is used in both the diagnosis and treatment of thyroid cancer. The thyroid will normally absorb some iodine to produce iodine-containing thyroid hormones. An overactive thyroid gland will absorb a larger amount of the radioactive material. If this is the case, more and more radioactive iodine can be administered, where it will cluster in the diseased portion of the thyroid tissue and kill some of the nearby cells. Cancer treatments often cause patients to feel very sick, because while the radiation treatment kills the unwanted cancer cells, it causes damage to some healthy cells in the process. 
Story: John is a doctor in a local hospital. Today, he is seeing two patients, patient A and patient B. Patient A has thyroid cancer, but patient B does not have thyroid cancer. John is trying to see the difference between these two patients' reports. 
Question: Which patient would risk damaging healthy cells, patient A or patient B?
[A]: patient A.


[Q]: Background Paragraph: Another example of negative feedback has to do with blood glucose levels. When glucose (sugar) levels in the blood are too high, the pancreas secretes insulin to stimulate the absorption of glucose and the conversion of glucose into glycogen, which is stored in the liver. As blood glucose levels decrease, less insulin is produced. When glucose levels are too low, another hormone called glucagon is produced, which causes the liver to convert glycogen back to glucose. 
Story: Tim and Fred were two students. Tim studied about negative feedback and the pancreas, while Fred studied about the stomach and the jejunum. 
Question: Which student read more about glycogen being stored in the liver?
[A]:
Tim.