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Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions.       People who daydream are often thought of in negative terms, such as being lazy or not doing what they should be doing. However, scientists who study the brain have learned many interesting things, especially from studying the brains of daydreamers. In fact, far from being a waste of time, some scientists believe that daydreaming is a healthy and useful activity for all of our brains.       In order to study the brain, scientists use special devices that scan the brain and show pictures of which parts of the brain are active at certain times. By using this technique, they proved that when a person is daydreaming, the device will show a distinct pattern of activity in the brain called the "default" mode of thinking. In the default mode, the top or outside part of the brain is very active. Actually, several regions of the brain are interacting in this mode. Some scientists describe this mode as a time when the brain focuses on itself rather than focusing on the environment around the person. Typically, this occurs when a person is doing simple, tedious work or performing routine actions that don't need much attention, like walking to school or cooking simple foods. People tend to daydream during such activities.       The importance of daydreaming lies in developing both creative and social skills. When the mind is not engaged in dealing with one's immediate situation or problem, then it is free to wonder about things. A time of wandering allows the mind to create things. New inventions may be imagined, or possible solutions to a problem can be planned. For example, solutions for problems in relationships with other people may come to mind. In fact, most daydreams involve situations with others. Perhaps these are daydreams based on memories of the past, or daydreams of what might be in the future. In either case, daydreams help us develop the appropriate skills we can use in real interactions with others.       As neurologist Dr. Marcus Raichle of Washington University explains: "When you don't use a muscle, that muscle really isn't doing much. But when your brain is supposedly doing nothing and daydreaming, it's really doing a tremendous amount." During the so-called "resting state" the brain isn't resting at all! What does the passage mainly discuss? 

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Read the following passage and mark the letter A, B, C or D on you answer sheet to indicate the correct answer to each of the questions.  SCIENTIFIC DISCOVERIES      A satellite is best understood as a projectile, or an object that has only one force acting on gravity. Technically speaking, anything that crosses the Karman Line at an altitude of kilometers (62 miles) is considered in space. However, a satellite needs to be going fast — at least 8 km (5 miles) a second - to stop from falling back down to Earth immediately.       If a satellite is traveling fast enough, it will perpetually "fall" toward Earth, but the Earth's curvature means that the satellite will fall around our planet instead of crashing back on the surface. Satellites that travel closer to Earth are at risk of falling because the drag of atmospheric molecules will slow the satellites down. Those that orbit farther away from Earth have fewer molecules to contend with.       There are several accepted "zones" of orbits around the Earth. One is called low-Earth-orbit, which extends from about 160 to 2,000 km (about 100 to 1,250 miles). This is the zone where the ISS orbits and where the space shuttle used to do its work. In fact, all human missions except for the Apollo flights to the moon took place in this zone. Most satellites also work in this zone.       Geostationary or geosynchronous orbit is the best spot for communications satellites to use, however. This is a zone above Earth's equator at an altitude of 35,786 km (22,236 mi). At this altitude, the rate of "fall" around the Earth is about the same as Earth's rotation, which allows the satellite to stay above the same spot on Earth almost constantly. The satellite thus keeps a perpetual connection with a fixed antenna on the ground, allowing for reliable communications. When geostationary satellites reach the end of their life, protocol dictates they're moved out of the way for a new satellite to take their place. That's because there is only so much room, or so many "slots" in that orbit, to allow the satellites to operate without interference.       While some satellites are best used around the equator, others are better suited to more polar orbits - those that circle the Earth from pole to pole so that their coverage zones include the north and south poles. Examples of polar-orbiting satellites include weather satellites and reconnaissance satellites.  (Source: https://www.space.com/24839-satellites.html)  Which of the following best serves as the title for the passage?

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