[1] Research
suggests that humans aren’t the only members of several species in the animal
kingdom which exhibit handedness, meaning the preference for one hand over the
other. Handedness is related to lateral asymmetry, which refers to physical and
functional aspects between sides of the brain. It appears that nine out of ten
humans throughout history have preferred to use their right hand, and that
eight of ten were right foot dominant. A genetic link, or some kind of
inherited trait, has been attributed to hand preference, though there is no
guarantee that a right or left handed person’s child will have the same hand
preference. On the other hand, left-handedness does tend to run in families. In
fact, around 6 percent of children whose parents are both right hand dominant
will end up left-handed. Meanwhile, among children with two left-handed
parents, up to 40 percent grow up left-handed, too. The occurrence of
left-handed children with one left-handed and one right-handed parent typically
ranges from about 15 to 20 percent. Amazingly enough,one in six pairs of
identical twins will differ in their handed preference in spite of having the
same genes.
[2] If hand
preference goes beyond genetics alone, there must be other unknown variables at
play. To learn more, researchers have closely studied the brain in regards to
this subject. French anthropologist, Dr. Paul Broca, found that patients who
had lost the ability to speak due to a stroke would also become paralyzed on
the right side of their body. From this, Broca realized that because the left
hemisphere of the brain controls the right half of the body and vice versa, the
brain damage must have been in the brain’s left hemisphere. Psychologists have
theorized that 95 percent of right-handed people’s language centers are in the
left hemisphere of their brains, while 5 percent have language centers on the
right side. Surprisingly enough, left-handed people do not show the exact
reverse of this, and instead, a majority have their language center located in
the left hemisphere, with some 30 percent in the right hemisphere.
[3] At the
Australian National University in Canberra, Dr. Brinkman has suggested that
human speech evolved alongside a preference for the right hand. From
her research, Brinkman believes that one side of the brain became specialized
for fine motor skills, which are necessary for speech and as the brain
continued to evolve for speech, the right-hand preference emerged. According
to Brinkman, the majority of left-handed people exhibit left hemisphere
dominance with some capacity in the right hemisphere as well. Dr. Brinkman has
observed that a left-handed person with brain-damage to the left hemisphere is
often able to recover speech ability more effectively. She thinks this
phenomenon can be explained by left-handed people’s tendency towards bilateral
speech function.
[4] Dr.
Brinkman research has expanded her research into primates as well. In her
studies of macaque monkeys, she found that the year-old babies appeared to
learn either hand preference from their mothers. In humans, on the other hand,
specialization of the two hemispheres’ functions actually creates physical
differences in the anatomy of the brain, with areas associated with speech
production often being larger on the left side than on the right. Because
monkeys and apes do not have the ability of speech, one would not expect to see
such a variation in these animals. However, Brinkman believes that she has
discovered a trend in monkeys’ brains which suggests the same asymmetry seen in
human brains.
[5] Recent
research on human embryos led to the discovery that a left-right asymmetry is
evident before birth. However, there are many other variables which can affect
brain development along the way. Initially, all brains begin as female,
becoming male brains if the male fetus secretes hormones. The sides of the
brain mature at different rates; the right hemisphere develops first, then the
left. Moreover, a female brain develops slightly more quickly than a male
brain. During a fetal brain’s development, a male brain is more likely to be
affected, and the left hemisphere is also more likely to be affected. The brain
may lose some lateralization, resulting in left-handedness as well as a
tendency towards skills which are typically associated with the left brain
hemisphere, such as logic, rationality, and abstraction. It is possible that
this explanation captures why professionals such as mathematicians and
architects tend to be left-handed more often, as well as a higher occurrence of
left-handed males than females.
[6] Throughout
our history, our language subliminally reinforces the notion that the right
side is good, while the left is potentially dangerous. In fact, the Latin word
“sinister” actually means “left.” It is no coincidence that left-handed
children, forced to use their right hand, often develop a stammer as they are
robbed of their freedom of speech.” However, as more research is undertaken on
the causes of left-handedness, attitudes towards left-handed people are
gradually changing for the better.
1 What can
be inferred from paragraph 1 about the correlation between genes and hand
preference?
- Genes are the single most powerful
determinant of hand preference in humans.
- Genes have a degree of influence on
hand preference in some humans.
- Genes have no decisive effect on
how hand preference develops in humans.
- Genes and hand preference have a
rather ambiguous link between one another.
ANSWER
EXPLANATION
Question is
worth: 1 point.
Correct Answer:
b
Your Selection: Not Answered
(A) is
incorrect: the paragraph makes no such claim; on the contrary, it says “there
is no guarantee that a right or left handed person's child will have the same
hand preference.”
(B) is correct: the paragraph says “a genetic link, or some kind of inherited
trait, has been attributed to hand preference,” but it also says “there is no
guarantee that a right or left handed person's child will have the same hand
preference.”
(C) is incorrect: the paragraph makes no such claim; quite the opposite, it
says “a genetic link, or some kind of inherited trait, has been attributed to
hand preference.”
(D) is incorrect: the paragraph points out that a few correlations between
genes and hand preference can be observed, as in “left-handedness does tend to
run in families.”
2 According
to paragraph 1, how do the hand preferences of parents affect the ones of
children?
- Children of left-handed parents
have the highest chance of being left-handed.
- Children of right-handed parents
have no chance of becoming left-handed.
- Children of parents with different
hand preferences still grow up right-handed.
- Children who are twins exhibit hand
preferences of their parents identically.
ANSWER
EXPLANATION
Question is
worth: 1 point.
Correct Answer:
a
Your Selection: Not Answered
(A) is correct:
the paragraph says “among children with two left-handed parents, up to 40
percent grow up left-handed,” which is the highest percentage among all similar
scenarios that the paragraph mentions.
(B) is incorrect: the paragraph says “around 6 percent of children whose
parents are both right hand dominant will end up left-handed.”
(C) is incorrect: the paragraph says “the occurrence of left-handed children
with one left-handed and one right-handed parent typically ranges from about 15
to 20 percent.”
(D) is incorrect: the paragraph says “one in six pairs of identical twins will
differ in their handed preference in spite of having the same genes.”
3 The word
'variables' in paragraph 2 is closest in meaning to:
- subtleties
- aspects
- factors
- conditions
ANSWER
EXPLANATION
Question is
worth: 1 point.
Correct Answer:
c
Your Selection: Not Answered
(A) is
incorrect: “subtlety” typically refers to a small detail or feature that is
difficult to notice.
(B) is incorrect: “aspect” mainly refers to a particular part, feature, or
quality of something.
(C) is correct: “factor” can mean one of the things that influence whether an
event happens or the way that it happens, which is the closest in meaning to
“variable” among all four.
(D) is incorrect: “condition” usually refers to the physical state of
something.
4 Which of
the following sentences best expresses the essential information that the
highlighted sentence in paragraph 3 conveys? Incorrect choices alter the
meaning in important ways or leave out essential information.
From her
research, Brinkman believes that one side of the brain became specialized for
fine motor skills, which are necessary for speech and as the brain continued to
evolve for speech, the right-hand preference emerged.
- Brinkman's research has pointed out
that the side of the brain specialized for fine motor skills is just as
essential for speech as it is for right-hand preference.
- Brinkman has discovered from her
research that the brain's specialization for fine motor skills, speech,
and right-hand preference are closely related and their development
happens side by side.
- Brinkman's research has led her to
believe that the right-hand preference has appeared alongside the brain's
involvement for speech in the side of the brain specialized for fine motor
skills.
- Brinkman has found out that the
right-hand preference and the ability for speech are associated with the
same side of the brain as specialization for fine motor skills.
ANSWER
EXPLANATION
Question is
worth: 1 point.
Correct Answer:
c
Your Selection: Not Answered
(A) is
incorrect: the original meaning is altered, since the new sentence shifts its
focus towards how important the side of the brain that controls fine motor
skills is for speech and right-hand preference alike.
(B) is incorrect: the original meaning is altered, since the new sentence
assumes what the original sentence does not suggest – that fine motor skills,
speech, and right-hand preference are integrated functions.
(C) is correct: the original meaning is preserved, since the new sentence still
emphasizes what the original sentence points out – that the right-hand
preference emerged as the brain continued to evolve for speech.
(D) is incorrect: the original meaning is altered, since the new sentence
highlights the association between the side of the brain responsible for fine
motor skills on the one hand and the right-hand preference and the ability for
speech on the other hand.
5 According
to paragraph 4, what has Dr. Brinkman uncovered during her research into
primates?
- Hemispheric specialization fosters
physical differences in the brain's anatomy.
- Monkeys and apes do not possess the
ability for speech.
- Infant macaque monkeys pick up hand
preferences from their mothers.
- Centers in the brain linked to
speech production are larger on the left side.
ANSWER
EXPLANATION
Question is
worth: 1 point.
Correct Answer:
c
Your Selection: Not Answered
(A) is
incorrect: the paragraph mentions this fact in relation to humans and does not
associate it with Dr. Brinkman's research into primates.
(B) is incorrect: the paragraph points out this fact, but it does not connect
it to Dr. Brinkman's research into primates in any way.
(C) is correct: the paragraph says “in her studies of macaque monkeys, she
found that the year-old babies appeared to learn either hand preference from
their mothers.”
(D) is incorrect: the paragraph includes this fact, but it does so in reference
to humans, without associating it with Dr. Brinkman's research into primates by
any means.
6 Examine
the four █ in the selection below and indicate at which block the following
sentence could be inserted into the passage:
As it turns out, handedness isn't nearly as unique to humans as it has long
been believed by the science.
Dr. Brinkman
research has expanded her research into primates as well. █ [A] In
her studies of macaque monkeys, she found that the year-old babies appeared to
learn either hand preference from their mothers. █ [B] In humans, on
the other hand, specialization of the two hemispheres’ functions actually
creates physical differences in the anatomy of the brain, with areas associated
with speech production often being larger on the left side than on the right.
Because monkeys and apes do not have the ability of speech, one would not
expect to see such a variation in these animals. █ [C] However,
Brinkman believes that she has discovered a trend in monkeys’ brains which
suggests the same asymmetry seen in human brains. █ [D] .
- [A]
- [B]
- [C]
- [D]
ANSWER
EXPLANATION
Question is
worth: 1 point.
Correct Answer:
d
Your Selection: Not Answered
(A) is
incorrect: inserting the missing sentence here would disrupt the logical connection
between the preceding sentence and the following sentence, that form a flow.
(B) is incorrect: placing the missing sentence here would not be logically
suitable, making the beginning of the following sentence – “in humans, on the
other hand” – sound redundant.
(C) is incorrect: using the missing sentence here would stand in the way of the
logical sequence between the preceding sentence and the following sentence,
that are in opposition to each other.
(D) is correct: utilizing the missing sentence here appears the most suitable,
since in this spot the missing sentence can serve as a form of rhetorical
statement, concluding the paragraph.
7 Paragraph
5 implies that lateralization in the human brain:
- Becomes noticeable when an aptitude
for certain skills comes out.
- Unfolds at a different rate for
every individual.
- Is more likely to occur in a male
rather than a female brain.
- Takes place during the brain's
formation in the fetal stage.
ANSWER
EXPLANATION
Question is
worth: 1 point.
Correct Answer:
d
Your Selection: Not Answered
(A) is
incorrect: the paragraph says that “a left-right assymetry is evident before
birth” and mentions aptitude for certain skills only in the context of how the
brain losing some lateralization results in “a tendency towards skills which
are typically associated with the left brain hemisphere.”
(B) is incorrect: the paragraph makes no such statement, mentioning “different
rates” only in relation to how “the sides of the brain mature at different
rates.”
(C) is incorrect: the paragraph says that a male brain is actually more likely
to lose some lateralization, since “a female brain develops slightly more
quickly than a male brain” and “a male brain is more likely to be affected.”
(D) is correct: the paragraph mentions that “a left-right assymetry is evident
before birth” and goes into detail about lateralization “during a fetal's brain
development.”
8 All of
the following are mentioned in paragraph 5 as peculiarities of brain
development EXCEPT:
- Without the production of specific
hormones by the fetus, the brain is bound to remain female.
- A male brain is more susceptible to
various influences and takes longer to mature.
- Fetal gender determines the rate at
which the right and the left hemispheres develop.
- Losing a degree of lateralization
in the brain makes left-handedness more likely to occur.
ANSWER
EXPLANATION
Question is
worth: 1 point.
Correct Answer:
c
Your Selection: Not Answered
(A) is
incorrect: the paragraph says “all brains begin as female, becoming male brains
if the male fetus secretes hormones.”
(B) is incorrect: the paragraph says that “a female brain develops slightly
more quickly than a male brain” and that “a male brain is more likely to be
affected.”
(C) is correct: the paragraph makes no such claim, pointing out instead that
“the right hemisphere develops first, then the left” in female and male brains
alike.
(D) is incorrect: the paragraph says “the brain may lose some lateralization,
resulting in left-handedness.”
9 In
paragraph 6, the author says “our language subliminally reinforces the notion
that the right side is good” to:
- Highlight that the bias against
left-handed people goes back to the times of ancient Rome.
- Point out that the view of
left-handedness as an abnormality hasn't relied on research.
- Suggest that left-handedness is
poorly researched due to the notion that it's potentially dangerous.
- Emphasize that the forced use of
the right hand in left-handed kids causes them to stammer.
ANSWER
EXPLANATION
Question is
worth: 1 point.
Correct Answer:
b
Your Selection: Not Answered
(A) is
incorrect: the paragraph includes no such suggestion; by pointing out that the
Latin word “sinister” means “left,” the author merely supports the paragraph's
key message that “our language subliminally reinforces the notion that the
right side is good, while the left is potentially dangerous.”
(B) is correct: the author concludes the paragraph by highlighting that “as
more research is undertaken on the causes of left-handedness, attitudes towards
left-handed people are gradually changing for the better,” pointing out that
the bias against left-handedness has not been based on research.
(C) is incorrect: the paragraph makes no such statement; in fact, it suggests
the opposite – that left-handedness is viewed as potentially dangerous
precisely because it is poorly researched.
(D) is incorrect: the paragraph does mention this detail, but it places no
emphasis on it; this detail is also not the biggest point that the author is
trying to make in the paragraph.
10Directions: An
introductory sentence for a brief summary of the passage is provided below.
Complete the summary by selecting the THREE answer choices that express the
most important ideas in the passage. Some sentences do not belong in the
summary because they express ideas that are not presented in the passage or are
minor ideas in the passage. This question is worth 2 points.
Drag your
answer choices to the spaces where they belong. To remove an answer choice,
drag it back. To review the passage, click VIEW TEXT.
Handedness, a
phenomenon closely associated with lateral asymmetry in humans and some animal
species, has been quite puzzling for scientists.
- C. From genetics to fetal brain
development, multiple factors appear to have a stake in which hand becomes
the preferred one.
- E. Until recently, the causes of
handedness have seen almost no research due to the long-held irrational
beliefs about the phenomenon.
- F. As the understanding of
handedness increases, its relation to aptitude for certain occupations becomes
more apparent, leading to a better perception of left-handed individuals.
- A. While there is a clear link
between genetics and handedness, a theory that could accurately predict
hand preference in humans is yet to emerge.
- B. Despite the impact of genetics,
handedness seems to be closer associated with the development of speech
and language centers of the brain.
- C. From genetics to fetal brain
development, multiple factors appear to have a stake in which hand becomes
the preferred one.
- D. As research suggests, monkeys in
particular seem to manifest the same lateral asymmetry patterns, including
handedness, as the ones observed in humans.
- E. Until recently, the causes of
handedness have seen almost no research due to the long-held irrational
beliefs about the phenomenon.
- F. As the understanding of
handedness increases, its relation to aptitude for certain occupations
becomes more apparent, leading to a better perception of left-handed
individuals.
ANSWER
EXPLANATION
Question is
worth: 2 points.
Correct Answer:
c,e,f
Your Selection: Not Answered
(A) is
incorrect: paragraph 1 of the passage does go over the role of genetics in the
development of hand preference in humans, but it makes no speculations about a
theory that could predict hand preference.
(B) is incorrect: paragraphs 2 and 3 of the passage discuss the connection
between handedness and speech and language centers of the brain, but they
mention nothing about this influencing factor as being more powerful than
genetics.
(C) is correct: paragraphs 1 through 5 of the passage examine the degree of
influence that certain key factors, including genetics and brain development
during the fetal stage, appear to have on hand preference.
(D) is incorrect: paragraph 4 of the passage mentions this hypothesis of Dr.
Brinkman as a minor detail without elaborating on it.
(E) is correct: paragraph 6 of the passage points out that the bias towards the
right side as “good” and against the left side as “sinister” has been present
throughout history, and that research into handedness has intensified not very
long ago.
(F) is correct: paragraph 5 of the passage suggests that recent research helps
explain the connection between handedness and a tendency towards certain skills
and professions, while paragraph 6 says that more research helps improve the
attitude towards left-handed people.
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