Larvae of many marine invertebrate species delay their metamorphosis into juveniles when cues signaling an appropriate juvenile environment are absent, thereby increasing their likelihood of thriving as juveniles and of ultimately reaching adulthood. Nevertheless, delayed metamorphosis has potential costs for juveniles, including reduced growth and increased mortality. Nearly all evidence of such costs involves species whose larvae do not feed but rather subsist on stored nutrients, indicating that insufficient energy reserves may be an underlying cause of these costs. Supporting this hypothesis are laboratory studies showing that in a certain bryozoan, the prolonged larval swimming that results from delayed metamorphosis is associated with size reductions in the juvenile feeding organ (the lophophore) and that one factor influencing the size of juveniles of certain barnacle species is how long larvae delay metamorphosis.However, other studies show that while significantly fewer juvenile Capitella worms survived to adulthood when metamorphosis had been delayed, prolonged larval swimming had no significant effect on juvenile size, suggesting, perhaps, that in some species, factors other than insufficient energy reserves account for the negative effects of the larval stresses that result from delayed metamorphosis.
[阅读&逻辑 ]经典真题260篇 -8830
Which of the following statements best describes the function of the highlighted sentence in the context of the passage as a whole?
[阅读&逻辑 ]经典真题260篇 -8831
In the context in which it appears, “formula” most nearly means
[阅读&逻辑 ]经典真题260篇 -8829
The passage implies which of the following about the introduction of floral-patterned rugs in Timurid royal courts?
[阅读&逻辑 ]经典真题260篇 -8828
According to the passage, after the 1440s, Timurid paintings of court scenes
[阅读&逻辑 ]经典真题260篇 -8827
Which of the following, if true, provides the most support for the argument?
[阅读&逻辑 ]经典真题260篇 -8826
Which of the following, if true, most strengthens the argument?
[阅读&逻辑 ]经典真题260篇 -8825
With which of the following statements about Impressionist painting would the author of the passage be most likely to agree?
[阅读&逻辑 ]经典真题260篇 -8824
The “tradition” refers to the
[阅读&逻辑 ]经典真题260篇 -8823
The primary purpose of the passage is to
[阅读&逻辑 ]经典真题260篇 -8822
The passage is primarily concerned with
[阅读&逻辑 ]经典真题260篇 -8821
The “hypothesis” implies that compared to marine invertebrate larvae that subsist on stored nutrients, marine invertebrate larvae that feed are less likely to
[阅读&逻辑 ]经典真题260篇 -8820
The passage suggests that the “bryozoan,” the “barnacle species,” and “Capitella worms” all share which of the following characteristics?
[阅读&逻辑 ]经典真题260篇 -8819
It can be inferred from the passage that if Keay’s proposed explanation of meteor sounds is correct, it is true that
[阅读&逻辑 ]经典真题260篇 -8818
The passage suggests that Keay formulated his hypothesis in response to
[阅读&逻辑 ]经典真题260篇 -8817
Which of the following best describes the function of the highlighted sentence?
[阅读&逻辑 ]经典真题260篇 -8816
According to the passage, the disappearance after 1993 of known evening bat roosts in buildings suggests which of the following?
[阅读&逻辑 ]经典真题260篇 -8815
The author mentions the fact that evening bats radio-tracked since 1993 have roosted in trees primarily in order to
[阅读&逻辑 ]经典真题260篇 -8814
According to the passage, payments to wage laborers in the early United States were
[阅读&逻辑 ]经典真题260篇 -8813
The passage suggests which of the following about records of payments for outwork?
[阅读&逻辑 ]经典真题260篇 -8812
The author of the passage mentions companies’ recognition that “the results of scientific investigation were necessarily uncertain” primarily in order to