In this task, you're given an article, a question which often contains a blank and four options (associated with "A", "B", "C", "D"). Your task is to find the correct answer (from the given options) for the question from the given article and return one of the options from "A", "B", "C", and "D". Do not generate anything else apart from one of the following characters: "A", "B", "C", "D". There is only one correct answer for each question.
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Question: Article: How men first learned to invent words is unknown; in other words, the origin of language is a mystery. All we really know is that men, unlike animals, somehow invented certain sounds to express thoughts and feelings, actions and things, so that they could communicate with each other; and that later they agreed upon certain signs, called letters, which could be combined to represent those sounds, and which could be written down. Those sounds, whether spoken, or written in letters we call words. The power of words, then, lies in their combinations - the things they bring up before our minds. Words become filled with meaning for us by experience; and the longer we live, the more certain words recall to us the glad and sad events of our past; and the more we read and learn, the more the number of words that mean something to us increases. Great writers are those who not only have great thoughts, but also express these thoughts in words which appeal powerfully to our minds and feelings. This charming and telling use of words is what we call literary style. Above all, the real poet is a master of words. He can convey his meaning in words which sing like music, and which by their position and association can move men to tears. We should therefore learn to choose our words carefully and use them accurately, or they will make our speech silly and rude.
Question: The origin of language _ .
Options: (A) is reflected in sounds and letters (B) is handed down from generation to generation (C) dates back to the prehistoric period (D) is a problem not yet solved

Answer: D

Question: Article: In many romantic movies or TV shows one scene always appears. It involves a handsome man standing outside a young woman's window, singing a love song to her to win her over. However, trying to woo a female with songs is not just something that humans do. A few animals sing love songs as well. Birds and elephants are romantic but the latest animal to _ a female might surprise you--it is the humble mouse. You may find it odd to find out that mice sing. We do not hear them because the frequency of their voice is so high. In fact, scientists have known for some time that male mice make special sounds to females, but it has always been assumed that the sounds are produced instinctively and randomly, with little thought going into the process. But new research suggests otherwise. When male mice with different voices were put in a cage together, scientists found that they would gradually change their pitches to sound like one another. But when a female mouse was put in the cage with two males, one male would change his pitch to match the other. "It was usually the smaller animal changing the pitch to match the larger animal," professor Erich Jarvis, leader of the study, from Duke University, US, told BBC News. This ability, known as vocal learning, is rare in the natural world. It had been thought to be limited to some birds, such as parrots--as well as whales and dolphins. The latest findings challenge the long-held opinion that mice cannot learn to adapt their voices. Scientists also found the part of the brain that controls the mice's singing ability. In the experiment, they damaged the cells in this part of the mice's brain and found that the animals couldn't keep their songs in pitch or repeat them any more. This also happened when the mice became deaf. Jarvis said that this finding had changed his understanding of the way mice make sound. "In mice we find that the pathways that are at least modulating these vocalizations are in the forebrain, in places where you actually find them in humans," he said. "If we're not wrong, these findings will be a big boost to scientists studying diseases like autism and anxiety disorders."
Question: Which of the following is proven wrong by the latest discovery?
Options: (A) The frequency of mice's voice is so high that it's impossible for humans to hear it. (B) When male mice make special sounds to females they can't control the sounds. (C) Birds and elephants are both romantic animals that are good at expressing love. (D) Animals like mice are smart even though they often make sounds randomly.

Answer: B

Question: Article: Have you ever wondered why stems grow upwards and roots downwards? Why plants always seem to turn, towards the light and climbing plants run up rather than down? The answer is simple:auxin,a chemical substance that controls growth in plants. Auxin gives away its secrets Auxin is a plant hormone . Darwin was already interested in it in the 19th century. Only in recent years, however, has the hormone started to give away its secrets ,thanks to intensive molecular research.Auxin is produced in the young,growing parts of plants and then transported throughout the plant-to a low -lying stem for example. The stem needs to straighten out as soon as possible to be able to absorb the topside,resulting in the underside growing faster and the stem straightening out. For the same reason, plants in front of windows will always turn to the light . This active regulation of auxin transport allows plants to take ideal advantage of local and changing conditions. A new means of transport for auxin? The transport of auxin through the plant plays a vital role. And ,from all appearances,it is not a simple matter. The researchers identified an important new link and means of transport for auxin: PILS proteins . PILS proteins are vital for auxin-dependent plant growth and adjust the intracellular storage of the hormone. It is exactly this compartmentalizing of auxin that seems functionally important for the various developmental processes. Growing crops more efficiently: the right amount of auxin in the right place Higher auxin levels at the right moment and in the right place result in better growth and greater harvest. Better adjustment of auxin levels would make plants grow more efficiently. The researchers hope to contribute to the development of more efficient growing processes by continuing to sort out auxin transport processes.
Question: Which of the following is true of ausin according to the text?
Options: (A) It helps the plant to bend at the right places while growing. (B) It prevents the roots of plants from growing faster. (C) It is no use when the surroundings have changed. (D) It helps the underside of plants grow faster than the topside.

Answer:
D