100% Free Test Prep MCAT Practice Test Questions

Question 1

The anthropomorphic bias of those who would relegate marsupials to an inferior evolutionary status is most

apparent in their recourse to data on brain structure and behavior. Unlike humans and other placentals,

marsupials lack the corpus callosum, which facilitates inter-hemisphere transfer of data acquired through the

senses. Yet it cannot be inferred that marsupials are thus deprived of such function. Didelphis Virginiana, one

of the opossums, makes use of the anterior commissure, an adaptation that is also found in reptiles and

monotremes. Diprodontons, including kangaroos and koalas, supplement the anterior commissure with the

fasciculus aberrans. While the modes of neocortical interconnection may be diverse, the work of Johnson,

Heath and Jones points to the conclusion that, functionally speaking the cortices and neocortices of both

groups of mammals exhibit parallel connections. Parker also notes “a similar range of brain size to body weight

ratios and of neocortical expansion”.

Another stigma borne by marsupials is the consensus that they are less intelligent than placentals. Yet Williams

argues that, all else being equal, natural selection will favor instinctive over learned behavior as being more

biologically efficient and that it is the accidental death of the young that is the prime selective pressure for the

evolution of intelligence. Seen in this light, marsupials have a competitive edge; their gestation period is brief

and the young remain in the pouch for an extended period exposed only to those dangers which also affect the

mother. There they are directly exposed to the mother’s food supply and can observe her behavior at leisure.

Placentals, on the other hand, not only have a longer gestation period but, once their young are born, must

often leave while foraging. Such absences increase the risk of mortality and decrease the opportunity to learn.

Thus, among placentals, selection would favor the apparent intelligence in the young and protective behavior in

the mother.

Marsupials are not known to exhibit maternal protective behavior. In fact, Serventy has reported that frightened

female kangaroos will drop their pouch-young as they flee, drawing a predator’s attention to the less able

offspring while the adult escapes. This behavior, whether purposeful or accidental, instantaneously relieves the

female marsupial of the mechanical difficulties of pregnancy with which her placental counterpart would be

burdened, while marsupials can replace any lost young quickly. Thus, in the absence of any need for close

maternal supervision, sacrificing their offspring in this manner may well have been favored in selection. Pointing

to the absence of the “virtue” of maternal protectiveness in marsupials is an instance of how mistaken are those

theorists who see similarities with humans as marks of evolutionary sophistication.

According to the passage, which of the following favor(s) the development of intelligence as a trait of placental

mammals?

I. The need to leave their young while foraging

II. The comparatively great risk of accidental death of the young

III. The opportunity for the young to observe the mother at leisure

Section: Verbal Reasoning

A : I only

B : III only

C : I and II only

D : II and III only

Answer: C

Question 2

The atomic size of an atom is:

Section: Physical Sciences

A : greater than the positive ion.

B : smaller than the positive ion.

C : greater than the negative ion.

D : equal to covalent radius.

Answer: B

Question 3

Section: Physical Sciences

A :

B :

C :

D :

Answer: B

Question 4

Although nihilism is commonly defined as a form of extremist political thought, the term has a broader meaning.

Nihilism is in fact a complex intellectual stance with venerable roots in the history of ideas, which forms the

theoretical basis for many positive assertions of modern thought. Its essence is the systematic negation of all

perceptual orders and assumptions. A complete view must account for the influence of two historical

crosscurrents: philosophical skepticism about the ultimacy of any truth, and the mystical quest for that same

pure truth. These are united by their categorical rejection of the “known”.

The outstanding representative of the former current, David Hume (1711-1776), maintained that external reality

is unknowable, since sense impressions are actually part of the contents of the mind. Their presumed

correspondence to external “things” cannot be verified, since it can be checked only by other sense

impressions. Hume further asserts that all abstract conceptions turn out, on examination, to be generalizations

from sense impressions. He concludes that even such an apparently objective phenomenon as a cause-andeffect relationship between events may be no more than a subjective fabrication of the observer. Stanley Rosen

notes: “Hume terminates in skepticism because he finds nothing within the subject but individual impressions

and ideas.”

For mystics of every faith, the “experience of nothingness” is the goal of spiritual practice. Buddhist meditation

techniques involve the systematic negation of all spiritual and intellectual constructs to make way for the

apprehension of pure truth. St. John of the Cross similarly rejected every physical and mental symbolization of

God as illusory. St. John’s spiritual legacy is, as Michael Novak puts it, “the constant return to inner solitude, an

unbroken awareness of the emptiness at the heart of consciousness. It is a harsh refusal to allow idols to be

placed in the sanctuary. It requires also a scorching gaze upon all the bureaucracies, institutions, manipulators,

and hucksters who employ technology and its supposed realities to bewitch and bedazzle the psyche.”

Novak’s interpretation points to the way these philosophical and mystical traditions prepared the ground for the

political nihilism of the nineteenth and twentieth centuries. The rejection of existing social institutions and their

claims to authority is in the most basic sense made possible by Humean skepticism. The political nihilism of the

Russian intelligentsia combined this radical skepticism with a near mystical faith in the power of a new

beginning. Hence, their desire to destroy becomes a revolutionary affirmation; in the words of Stanley Rosen,

“Nihilism is an attempt to overcome or repudiate the past on behalf of an unknown and unknowable, yet hopedfor, future.” This fusion of skepticism and mystical re-creation can be traced in contemporary thought, for

example as an element in the counterculture of the 1960s.

The passage implies that the two strands of nihilist thought

Section: Verbal Reasoning

A : are combined in nineteenth and twentieth century political nihilism.

B : remained essentially separate after the eighteenth century.

C : are necessary prerequisites for any positive modern social thought.

D : are derived from distinct Eastern and Western philosophical traditions.

Answer: A

Question 5

Which of the following cell types does NOT contain the diploid number of chromosomes?

Section: Biological Sciences

A : Spermatogonium

B : Spermatid

C : Zygote

D : Primary oocyte

Answer: B

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