12.Practice.Tests.for.the.SAT_2015-2016_1128p

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Section 8
Practice Test Four
Directions: The passages below are followed by questions based on their content; questions following a pair of related
passages may also be based on the relationship between the paired passages. Answer the questions on the basis of
what is stated or implied in the passages and in any introductory material that may be provided.
Questions 7-18 are based on the following passage.
The following passage is adapted from a psychologist's
discussion of the development of the human brain.
Although the brain comprises only 2 percent of
the human body's average weight, the billions of
neurons and trillions of synaptic connections that
Line are the human brain constitute a truly impres-
(5) sive organ. In terms of what it can do, the human
brain is in some ways unable to match the brain
functioning of "lower" animals; in other ways, its
capabilities are quite unrivaled. Salmon, caribou,
and migrating birds, for example, have naviga-
( 10) tional abilities unparalleled in our own species,
and even dogs and cats have senses of hearing and
smell known only, in human form, to comic book
superheroes. Yet no other animal on the planet can
communicate, solve problems, or think abstractly
(15) about itself and the future as we do. While these
relative strengths and weaknesses can be attributed
to the unique and complex structure of the human
brain, neuroscientists also have traced these characteristics
to the human brain's remarkable tlex-
(20) ibility, or what researchers call plasticity.
Encased in a hard, protective skull that by the
age of two is already 80 percent of its eventual
adult size, the human brain has little room for size
expansion even while the rest of the body, espe-
(25) cially during adolescence, is experiencing significant
changes in physical appearance. Nevertheless,
the human brain's plasticity allows for marked
capacity changes because of usage, practice, and
experience throughout one's entire life. This idea
(30) that the human brain continues to develop and,
some might say, improve over the course of one's
life is a relatively new concept. Neuroscientists,
even after brain size was no longer considered a
direct determiner of brain capacity, once believed
(35) that the basic structure and abilities of the adult
brain are developed early in life and not subject
to change. Then, several provocative experiments
dramatically complicated such thinking.
One of these experiments, for example, exam-
( 40) ined the various effects an enriched environment,
in this case an "amusement park" for rats, could
have on brain development. Researchers kept one
group of rats in an empty cage, devoid of any stimulus,
while another group lived in a cage filled with
( 45) ladders, platforms, boxes, and other toys. Over the
course of the experiment, researchers used magnetic
resonance imaging technology to observe the
brain development of the two groups. Those rats
that lived in the enriched environment full of stim-
(50) uli developed heavier, thicker brains with more
neurons and synaptic connections-the cellular
activity by which the brain functions-than those
that were deprived. Such results were then found
to be even more noticeable in humans, confirm-
(55) ing an essential point: one's life experiences and
environment not only mold the brain's particular
architecture but also can continue to spark the
expansion of its capacity to function.
7. The author's comparisons between the human
brain and those of other animals (lines 5-15) are
meant to
(A) suggest that despite areas of weakness the
human brain is the most sophisticated
(B) emphasize the diversity of brain types found
in the animal kingdom
(C) reiterate that it is not only the human brain
that displays remarkable plasticity
(D) illustrate the unique characteristics and capabilities
of the human brain
(E) praise the sensory abilities of the human
brain over those of other animals
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