instruction:
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.
question:
Background Paragraph: Like water in the ocean, air in the atmosphere exerts pressure that increases with depth. Most gas molecules in the atmosphere are pulled close to Earth’s surface by gravity. As a result, air pressure decreases quickly at lower altitudes and then more slowly at higher altitudes. This is illustrated in Figure below . Air pressure is greatest at sea level, where the depth of the atmosphere is greatest. At higher altitudes, the pressure is less because the depth of the atmosphere is less. For example, on top of Mount Everest, the tallest mountain on Earth, air pressure is only about one-third of the pressure at sea level. At such high altitudes, low air pressure makes it hard to breathe and is dangerous to human health. 
Story: Robert and his brother Timothy are both marathon runners. As marathon running is an endurance event, a key component is being able to replenish your oxygen supply by taking frequent breaths. This week, Robert is running a marathon in Colorado, which has low air pressures. Timothy is  also running a marathon, but he is running in Florida, which has high air pressures. 
Question: Who will have less difficulty in keeping a steady supply of oxygen during their marathon?
answer:
Timothy.


question:
Background Paragraph: Some species of ants farm aphids, protecting them on the plants where they are feeding, and consuming the honeydew the aphids release from the terminations of their alimentary canals. This is a mutualistic relationship, with these dairying ants milking the aphids by stroking them with their antennae. Although mutualistic, the feeding behaviour of aphids is altered by ant attendance. Aphids attended by ants tend to increase the production of honeydew in smaller drops with a greater concentration of amino acids.Some farming ant species gather and store the aphid eggs in their nests over the winter. In the spring, the ants carry the newly hatched aphids back to the plants. Some species of dairying ants (such as the European yellow meadow ant, Lasius flavus) manage large herds of aphids that feed on roots of plants in the ant colony. Queens leaving to start a new colony take an aphid egg to found a new herd of underground aphids in the new colony. These farming ants protect the aphids by fighting off aphid predators. 
Story: Pam and Ellie are two entomologists. they are both studying ants at the moment: Ellie is studying leafcutter ants, while Pam is studying ants that farm aphids. 
Question: Which scientist read less about aphid honeydew?
answer:
Ellie.


question:
Background Paragraph: ANOVA generalizes to the study of the effects of multiple factors. When the experiment includes observations at all combinations of levels of each factor, it is termed factorial. Factorial experiments are more efficient than a series of single factor experiments and the efficiency grows as the number of factors increases.[45] Consequently, factorial designs are heavily used. 
Story: Medication A was tested on 1000 people for 3 years and cured Disease X in 80% of those trials. However,  Medication B was tested on 50 patients and cured Disease X in 90% of those trials. 
Question: Was Medication A's trial more efficient or less efficient than Medication B's trial?
answer:

more efficient.