Problem: Background: Human populations are on the rise. The human population passed the 7 billion mark in October of 2011, and will pass 8 and 9 billion probably before the middle of the century. All these people will need resources such as places to live, food to eat, and water to drink, and they will use energy and create waste. Essentially, human population growth can effect all other causes of extinction. For example, more people on the Earth means more people contributing to global warming and pollution. More people also means more clearing of land for agriculture and development. Recall that development by humans often causes habitats to be destroyed. This destruction can force species to go extinct, or move somewhere else. Paragraph: There are two identical neighboring planets, Krypton and Gotham, inhabited by the same species of creature. Both civilizations utilize the same technology and have the same city structures. However, the creatures on Krypton use substantially more energy than the people on Gotham. Furthermore, the inhabitants of Krypton have started clearing more land than Gotham. Given the paragraph above, please answer correctly the following question: Which planet has a smaller population?

A: Gotham

Problem: Background: Currently, millions of individuals with high cholesterol take a similar type of drug, known as a statin. The drug, an inhibitor of HMG-CoA reductase (3-hydroxy-3-methyl-glutaryl-CoA reductase), the rate limiting enzyme in cholesterol biosynthesis, decreases blood levels of cholesterol by induce the expression of low density lipoprotein (LDL) receptors in the liver. The increased levels of the LDL-receptors stimulate the catabolism of plasma LDL, removing cholesterol from plasma, which is an important determinant of atherosclerosis. You may know of people who take a statin to help with their cholesterol levels. However, these drugs probably work slightly differently in many of those people. In some, it lowers their cholesterol significantly; in others it may lower it only moderately; and in some, it may have no significant effect at all. (Luckily for those individuals, there are multiple versions of the statins, so different drugs can be tested to find the proper combination for that individual.) Why the difference? Because of the genetic background of all people; the different single nucleotide polymorphisms that make us all different. Pharmacogenomics, a combination of pharmacology and genomics (the study of the genome) that refers to the study of the relationship between pharmaceuticals and genetics, may explain and simplify this problem. Paragraph: Two university students studied different types of drugs for their exams. Kate studied statins, while Carol studied anti-depressants. Given the paragraph above, please answer correctly the following question: Which student learned more about removing cholesterol from plasma?

A: Kate

Problem: Background: Recall that air pollution is due to chemical substances and particles released into the air mainly by human actions. When most people think of air pollution, they think of the pollution outdoors. But it is just as easy to have indoor air pollution. Your home or school classroom probably doesn't get much fresh air. Sealing up your home reduces heating and cooling costs. But this also causes air pollution to stay trapped indoors. And people today usually spend a majority of their time indoors. So exposure to indoor air pollution can become a significant health risk. Paragraph: James spent a lot of time indoors, and didn't get out much like Rob, his friend, who loved outdoors stuff. Given the paragraph above, please answer correctly the following question: Which friend was less exposed to indoor pollution?

A: Rob

Problem: Background: Noble gases are also used to fill the glass tubes of lighted signs like the one in the Figure below . Although noble gases are chemically nonreactive, their electrons can be energized by sending an electric current through them. When this happens, the electrons jump to a higher energy level. When the electrons return to their original energy level, they give off energy as light. Different noble gases give off light of different colors. Neon gives off reddish-orange light, like the word "Open" in the sign below. Krypton gives off violet light and xenon gives off blue light. Paragraph: John wanted to make some lighted signs for his business. To that end, he chose noble gases, neon, krypton, and xenon. First, he kept the noble gases in containers. He called it step A. Then he passed electric current through them. He called it step B. In the process, he came up with three signs, sign A, sign B, and sign C. Sign A used neon. Sign B used krypton, and sign C used xenon. Given the paragraph above, please answer correctly the following question: In which step the the electrons would not jump to higher energy level, step A or step B?

A:
step A