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 dangers of global warming are being increasingly studied by a wide global consortium of scientists. These scientists are increasingly concerned about the potential long-term effects of global warming on our natural environment and on the planet. Of particular concern is how climate change and global warming caused by anthropogenic, or human-made releases of greenhouse gases, most notably carbon dioxide, can act interactively, and have adverse effects upon the planet, its natural environment and humans' existence. It is clear the planet is warming, and warming rapidly. This is due to the greenhouse effect, which is caused by greenhouse gases, which trap heat inside the Earth's atmosphere because of their more complex molecular structure which allows them to vibrate and in turn trap heat and release it back towards the Earth. This warming is also responsible for the extinction of natural habitats, which in turn leads to a reduction in wildlife population.The most recent report from the Intergovernmental Panel on Climate Change (the group of the leading climate scientists in the world) concluded that the earth will warm anywhere from 2.7 to almost 11 degrees Fahrenheit (1.5 to 6 degrees Celsius) between 1990 and 2100. 
Story: Pam is an astronaut who has been given a mission to find a new planet for humans to live on. She is exploring the outer rims of the galaxy when she discovers two new planets that may be suitable. The atmospheric makeup of these planets is very similar to Pam's current home. After running a quick diagnostic, the only difference that Pam sees is that planet B has more carbon dioxide in its atmosphere than planet A. 
Question: Which planet has more heat inside its atmosphere?
[EX A]: planet B.

[EX Q]: Background Paragraph: Many reactions take place in solution or in the gas phase, where the reactants are evenly dispersed throughout a homogeneous mixture. However, for reactions in which one of the reactants is a pure solid or liquid (meaning that this reactant is not already mixed together with any other reactants), reactivity only occurs at the surface, where particles of the solid or liquid reactant come into contact with particles of the other reactants. All of the molecules or ions in the interior of the pure substance will not be colliding with the other necessary reactants, so they are not really contributing to the overall rate of the reaction. However, increasing the surface area will increase the frequency of potentially reactive collisions, because more reactant particles will be in contact with the other necessary reactants. 
Story: Mike was preparing for his chemistry exam. To see the chemistry concepts in practice he conducted two tests, test A and test B. In test A he used two liquid reactants evenly dispersed, but in test B he used one liquid reactant and one solid reactant. He was surprised to see that two tests had very different results. 
Question: Which test would have higher rate of reaction, test A or test B?
[EX A]: test A.

[EX Q]: Background Paragraph: In exercises such as weight lifting, skeletal muscle contracts against a resisting force (see Figure below ). Using skeletal muscle in this way increases its size and strength. In exercises such as running, the cardiac muscle contracts faster and the heart pumps more blood. Using cardiac muscle in this way increases its strength and efficiency. Continued exercise is necessary to maintain bigger, stronger muscles. If you don’t use a muscle, it will get smaller and weaker—so use it or lose it. 
Story: Phillip just came home to his apartment after taking a long, vigorous bike ride. He enters the front door to find his roommate, Brandon, sitting on the couch playing videogames and eating potato chips. Phillip tells Brandon that if he keeps being so lazy and snacking so much he's going to start looking chubby. Brandon just waves Phillip off and goes back to his game. 
Question: Are Phillip's cardiac muscles increasing or decreasing in strength?
[EX A]:
increasing.