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GMAT-Reading Comprehension
Our knowledge of the evolution of primate brains comes from two sources: the fossil record and comparisons between the brains of the various kinds of living primates. The fossil record of primate brains consists of casts of the insides of fossil braincases, called endocranial casts, or endocasts. These casts reproduce details of the surface of the brain, including the patterns of cerebral convolutions. Thus, fossil endocasts provide direct evidence of brain evolution, but the information they provide is only external. Comparative studies of the brains of living primates, on the other hand, while they can provide an enormous amount of information, can only be considered indirect evidence of brain evolution. Although it is tempting to arrange living species in a series of presumed primitive to advanced stages, a series of this sort may be misleading if they are taken to represent evolutionary lineages, because each species is specialized for its own ecological niche, and most species combine primitive and advanced features. [The difficult words in this passage are primates (family of living beings consisting of apes, monkeys and human beings), cerebral convolutions (folds in the brain), lineage (ancestry) and ecological niche (place in nature)] 7. The primary purpose of the passage is to (A) clarify methods used in the study of primate brain fossils (B) disqualify a theory of primate evolution (C) criticize techniques unproductive for the study of primate brain evolution (D) describe the progress of studies in primate evolution (E) evaluate sources of evidence for primate brain evolution This is a ‘primary passage’ question. In a short passage like this, we should look for the hint in the very first sentence or two. The first sentence of the passage mentions two sources of evidence regarding the evolution of primates - fossil endocasts and brains of living primates, and the subsequent sentences describe the strengths and the limitations of each one of these sources. In other words, the author of the passage evaluates the two sources of evidence. So, (E) is the answer. The next three questions(8,9 & 10)are also based on this passage.
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