exam questions

Exam MCAT Section 1 Verbal Reasoning All Questions

View all questions & answers for the MCAT Section 1 Verbal Reasoning exam

Exam MCAT Section 1 Verbal Reasoning topic 1 question 109 discussion

Actual exam question from Test Prep's MCAT Section 1 Verbal Reasoning
Question #: 109
Topic #: 1
[All MCAT Section 1 Verbal Reasoning Questions]

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 mothers 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 predators 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

  • A. I only
  • B. III only
  • C. I and II only
  • D. II and III only
Show Suggested Answer Hide Answer
Suggested Answer: C 🗳️
This is a Roman numeral question, and the information we need to answer it is contained in the second paragraph. The last three sentences of that paragraph contain the most important information for our purposes. There we are told that the placentals need to leave their young to go foraging; that immediately justifies statement I. Were told directly thereafter that this absence increases the risk of accidental death to the young. Hence, we can justify statement II as well. Note: At this point, only choice C meets our needs, but dont ignore statement III! Statement III, on the other hand, applies only to marsupials. We are told that the absence of the mother while she forages decreases the opportunity for placentals to learn by observing the mother. Therefore, statement III is not true.Kaplan Strategy:Use
"+" and "–" symbols to annotate true statements and false statements, respectively, on roman numeral questions. This will guide you to the correct answer choice more quickly and will also prevent you from having to read the question over and over again.

Comments

Chosen Answer:
This is a voting comment (?). It is better to Upvote an existing comment if you don't have anything to add.
Switch to a voting comment New
Currently there are no comments in this discussion, be the first to comment!
Community vote distribution
A (35%)
C (25%)
B (20%)
Other
Most Voted
A voting comment increases the vote count for the chosen answer by one.

Upvoting a comment with a selected answer will also increase the vote count towards that answer by one. So if you see a comment that you already agree with, you can upvote it instead of posting a new comment.

SaveCancel
Loading ...