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  3. Hydrothermal vents along the mid-ocean ridges host ephemeral ecosystems of diverse fauna, including several crustacean spe

Hydrothermal vents along the mid-ocean ridges host ephemeral ecosystems of diverse fauna, including several crustacean spe

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问题             Hydrothermal vents along the mid-ocean ridges host ephemeral ecosystems
      of diverse fauna, including several crustacean species, some of which undergo
      development as larvae up to 1,000 meters above and 100 kilometers away from
Line   the vents. For example, vent crab Bythograea thermydron (at stage of
(5)    larvae) possess image-forming compound eyes with a visual pigment sensitive to
      the blue light of upper oceanic waters. As these larvae metamorphose into
      adulthood and begin to descend to and settle at the vents, they lose their image-
      forming optics and develop high-sensitivity naked-retina eyes. With maturation,
      the spectral absorbance of the visual pigment in these eyes also shifts towards
(10)   longer wavelengths and this progressive visual metamorphosis trades imaging
      for increased sensitivity, and changes spectral sensitivity to the dim, longer
      wavelengths of light existing at the bottom of the ocean. As hydrothermal vents
      produce light, vision may supplement thermal and chemical senses to orient
      post-larval settlement at vent sites.
It may be inferred from the passage that the larval environment which surrounds the vent crab Bythograea thermydron differs from its adult environment in that it
选项 A、contains more thermal vents than the adult environment
B、receives more of its light from the sun than from hydrothermal vents
C、lacks the longer and dimmer wavelengths of light found in the adult environment
D、can be survived only by creatures equipped with image-forming optics
E、has a tendency to induce metamorphoses in the creatures that occupy it
答案B
解析
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