Time taken 11mins:
Q2 and 6 got wrong.
Q25: The passage suggests which of the following about the accuracy of the commuter diatom’s biological clock?
A: The accuracy of the commuter diatom’s biological clock varies according to changes in the tidal cycle.
B: The unusual accuracy that characterizes the commuter diatom’s biological clock is rare among intertidal species.C: The commuter diatom’s biological clock is likely to be more accurate than the biological clock of a species that is subject to less intense environmental pressures.
A commuter diatom has an unusually accurate biological clock, a consequence of the unrelenting environmental pressures to which it is subjected; any diatoms that do not burrow before the tide arrives are washed away.
D: The commuter diatom’s biological clock tends to be more accurate than the biological clocks of most other species because of the consistency of the tidal cycle.
E: The accuracy of the commuter diatom’s biological clock tends to fluctuate when the diatom is observed under variable laboratory conditions.
Q26: The author of the passage compares the relationship between an organism’s biological clock and its environment to the relation between a wristwatch and its owner most probably in order to
A: point out a fundamental difference between the function of biological clocks in organisms and the use of mechanical clocks by humansB: illustrate the way in which the period of an organism’s biological clock can be altered by environmental factors
relation between an organism’s biological clock and its environment is similar to that between a wristwatch and its owner: the owner cannot make the watch run faster or slower, but can reset the hands
C: suggest that there are important similarities between the biological clock in organisms such as the commuter diatom and the biological clock in humans
D: support an argument regarding the methods used by certain organisms to counteract the influence of the environment on their biological clocks
E: question the accuracy of the biological clock in organisms such as the commuter diatom
Q27: According to the passage, the periodic behavior displayed by commuter diatoms under constant laboratory conditions is characterized by which of the following?
A: Greater unpredictability than the corresponding behavior under natural conditionsB: A consistent periodic schedule in the short term
C: No difference over the long term from the corresponding behavior under natural conditions
D: Initial variability caused by the constant conditions of the laboratory
E: Greater sensitivity to environmental factors than is the case under natural conditions
>> I was inclined towards C. Appreciate inputs on this one.
28: The primary purpose of the passage is to
A: dispute the influence of environmental factors on the tide-associated behavioral rhythms displayed by the diatom Hantzschia virgata
B: describe how certain tide-associated behavioral rhythms displayed by the diatom Hantzschia virgata have changed over time
C: compare tide-associated behavioral rhythms to solar-day behavioral rhythms in the diatom Hantzschia virgataD: examine how certain biological and environmental influences affect the tide-associated behavioral rhythms displayed by the diatom Hantzschia virgata
This is not to suggest that the period of this biological clock is immutably fixed. Biologists have concluded that even though a diatom does not rely on the environment to keep time, environmental factors
E: identify certain environmental factors that limit the effectiveness of the biological clock in the diatom Hantzschia virgata
According to the passage, each of the following is characteristic of the tide-associated periodic behavior of commuter diatoms EXCEPT: A. It is triggered when the diatoms are inundated by the tide
B.It is correlated with the rise and fall of the tide
C. It adjusts to changes in the tidal cycle
D.It is influenced by the solar-day cycle
E.It is regulated by an innate time-keeping mechanism
Which of the following can be inferred from the passage about the effect of the solar-day cycle on the tide-associated periodic behavior displayed by commuter diatoms?
A The solar-day cycle makes this behavior less advantageous to the commuter diatoms at certain times of the year.
B The solar-day cycle makes this behavior somewhat more erratic.
C The solar-day cycle makes this behavior less important to the survival of the commuter diatoms.
D Because of the solar-day cycle, this behavior is forced to proceed at a more rapid pace at certain times during the 24-hour day. E Because of the solar-day cycle, this behavior is not expressed at certain times during the 24-hour day.
Diatoms of this species, sometimes called “commuter” diatoms, remain burrowed in the sand during high tide, and emerge on the sand surface during the daytime low tide.
these organisms are exposed to the solar-day cycle as well as to the tidal cycle, and sometimes display both solar-day and tidal periods in a single behavior. Commuter diatoms, for example, emerge only during those low tides that occur during the day.