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GMAT-Reading Comprehension
The next two questions(9 & 10) are also based on this passage.
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)]
8. According to the passage, endocasts are of limited value in the study of evolution because they are
(A) representative of only surface characteristics
(B) available for only a limited number of primates
(C) too crude to allow accurate comparisons
(D) too varied to reflect actual evolutionary sequences
(E) too indistinct to support meaningful conclusions
This is a ‘specific fact’ question, in which the key word is ‘endocasts’. The fourth sentence says, “The fossil endocasts provide direct evidence of brain evolution, but the information they provide is only external”. So, (A) is the answer.
The next two questions(9 & 10) are also based on this passage.
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