Read the following article and select the best answer. Article: Some colors people see late at night could cause signs of clinical depression . That was the finding of a study that builds on earlier study findings. They show that individuals who live or work in low levels of light overnight can develop clinical depression. Doctors use the word "clinical depression" to describe severe form of depression. Signs may include loss of interest or pleasure in most activities, low energy levels and thoughts of death or suicide. In the new study, American investigators designed an experiment that exposed hamsters to different colors. The researchers chose hamsters because they are nocturnal, which means they sleep during the day and are active at night. The animals were separated into four groups. One group of hamsters was kept in the dark during their night-time period. Another group was placed in front of a blue light, a third group slept in front of a white light, while a fourth was put in front of a red light. After four weeks, the researchers noted how much sugary water the hamsters drank. They found that the most depressed animals drank the least amount of water. Randy Nelson heads the Department of Neuroscience at Ohio State University. He says animals that slept in blue and white light appeared to be the most depressed. "What we saw is that these animals didn't show any sleep uneasiness at all but they did mess up biological clock genes and they did show depressive sign while if they were in the dim red light, they did not." Randy Nelson notes that photosensitive cells in the eyes have little to do with eyesight. He says these cells send signals to the area of the brain that controls what has been called the natural sleep-wake cycle. He says there's a lot of blue in white light. This explains why the blue light and white light hamsters appear to be more depressed than the hamsters seeing red light or darkness. Question: Researchers use hamsters in the experiment because _ . - they are similar to humans in dealing with colors - they are easy to observe and study - they are sensitive to colors like human beings - they are active at night and sleep during the day
they are active at night and sleep during the day

Read the following article and select the best answer. Article: The global energy crisis is approaching. What can we do? Here are some steps you can take. Cooling puts the greatest stress on your summer energy bill and the power grid . Just as t tune-up for your car can improve your gas mileage, a yearly tune-up of your heating and cooling system can improve efficiency and comfort. Clean or replaces filters monthly or as needed. For central air conditioning systems and room air conditioners, look for the ENERGY STAR, the federal government's symbol for energy efficiency. For central air, purchase the system with the highest possible Seasonal Energy Efficiency Raton. (SEER) Use energy-efficient ceiling fans either alone or with air conditioning. Ceiling fans do a great job of circulating air. When used with air conditioning, fans allow you to raise the thermostat and cut costs. Ceiling fans cool people, not rooms, so before you leave; turn off the ceiling fan. Let a programmable thermostat! "remember for you" to automatically adjust the indoor climate with your daily and weekend patterns to reduce cooling bills by up to 10 percent. You can come home to a comfortable house without wasting energy and cresting pollution all day while you are at work. Try to make your home airtight enough to increase your comfort, make your home quieter and cleaner and reduce your cooling costs up to 20 percent. Gut your air conditioning load, and reduce pollution by planting planting leafy trees around your home and fixing reflective bricks on your roof. Close blinds or shades on south-and west-facing windows during the day, or fix shading equipment to avoid heat build-up. Turn off everything not in use: lights, TVs, computers. And use fluorescent bulbs , which provide bright, warm light while using at least two-thirds less energy, producing 70 percent less heat and lasting up to 10 times longer than incandescent bulbs . Drive the car that gets better gas mileage whenever possible if you own more than one vehicle. If you drive 12,500 miles a year, switching 10 percent of your trips from a... Question: According to the passage, the thermostat is used to _ . - make rooms quieter - control room temperature - turn off the air conditioner - reduce room air pollution
control room temperature

Read the following article and select the best answer. Article: I have nothing to say about whether or not "A Day Without Immigrants " had a positive or negative effect on the question of how the federal government should deal with the huge population of undocumented illegal immigrants in this country. I'll leave that question to others. Regardless of how you feel about the event, one conclusion is obvious. Using the theme of "A Day Without" as a way to focus national attention on a particular subject is a great idea, and could serve as a method for increasing public consciousness about other issues that affect daily life in America. Here are my top three examples: "A Day Without Speeding." How hard could this be? If all drivers would strictly obey every posted speed limit on highways, downtown, on neighborhood streets, and in parking lots for one 24-hour cycle, the benefits would be huge. "A Day Without Losing Your Temper." A higher degree of difficulty here, and I know that from personal experience. When something goes wrong at home or on the job, there may be brief satisfaction in yelling or kicking the furniture, but bursting into anger usually has nothing to do with the approach to the heart of the matter. "A Day Without Having All The Answers." I would like to get a break from hearing anyone speak the phrase, "Here's what you're doing wrong." Right now the US is packed with citizens who believe they can point out the cause of every single problem in existence and then solve it in a moment. I believe they need to be quiet sometimes and use their ears instead of their voices. I wonder how would average Americans react to such a national pause? Would it be a day of reaction against anger, or joyful celebrations? Question: The author uses his "top three examples" to _ . - criticize the undocumented illegal immigrants in America - show public consciousness of some subjects could be raised - encourage common people to create more similar activities - indicate some bothering issues affecting people's daily life
show public consciousness of some subjects could be raised