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 Input:
Background Paragraph: Biodiversity loss is the extinction of species (plant or animal) worldwide, and also the local reduction or loss of species in a certain habitat.

The latter phenomenon can be temporary or permanent, depending on whether the environmental degradation that leads to the loss is reversible through ecological restoration / ecological resilience or effectively permanent (e.g. through land loss). Global extinction has so far been proven to be irreversible.

Even though permanent global species loss is a more dramatic phenomenon than regional changes in species composition, even minor changes from a healthy stable state can have dramatic influence on the food web and the food chain insofar as reductions in only one species can adversely affect the entire chain (coextinction), leading to an overall reduction in biodiversity, possible alternative stable states of an ecosystem notwithstanding. Ecological effects of biodiversity are usually counteracted by its loss. Reduced biodiversity in particular leads to reduced ecosystem services and eventually poses an immediate danger for food security, also for humankind.[1]. 
Story: Rob is an environmental scientist. He is studying the effect of insect species on environment. For his study he chose four locations, location A, location B, location C and the entire globe, which he denoted as location D. He noticed location A's loss of biodiversity is temporary , but location B's loss is permanent. Location C's loss of biodiversity yet to be determined. 
Question: Would ecological restoration be helpful or not helpful for location A?

Ex Output:
helpful.


Ex Input:
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?

Ex Output:
Black.


Ex Input:
Background Paragraph: Alcoholic beverages do not make the entire body warmer.[361] The reason that alcoholic drinks create the sensation of warmth is that they cause blood vessels to dilate and stimulate nerve endings near the surface of the skin with an influx of warm blood. This can actually result in making the core body temperature lower, as it allows for easier heat exchange with a cold external environment. 
Story: A scientist studied the effects of alcoholic beverages on the human body during severe weather exposure. He decided to experiment on himself. He stood in -30 degrees weather for 2 hours and called it experiment A. He then repeated the experiment, the only difference being that he consumed a pint of hard liquor before and during those two hours, and that was called experiment B. 
Question: When were the scientist's nerve endings near the surface of the skin stimulated less, during experiment A, or during B?

Ex Output:

experiment A.