原题
| Species | P50 (megapascal) | Mean elevation (m) | Rainforest occupancy (%) |
| Paracryphia alticola | -2.1 | 1,011 | 91 |
| Ascarina rubricaulis | -2.28 | 825 | 86 |
| Amborella trichopoda | -2.77 | 756 | 82 |
| Hedycarya parvifolia | -3.19 | 956 | 86 |
| Zygogynum crassifolium | -4.05 | 57 | 24 |
P50—the pressure in the xylem (water-conducting tissue) at which a plant loses 50% of its hydraulic conductivity due to embolisms (air bubbles in the water flow)—is a key index of xylem embolism resistance and, by extension, tolerance of water stress; lower P50 values indicate lower vulnerability to xylem embolisms. Studies have found that variation in this functional trait corresponds with the distribution of plant species along moisture and elevation gradients. A student hypothesizes that this pattern would persist in woody species in New Caledonia, which is home to moist tropical rainforests, dry forests, and a range of elevations. To test the hypothesis, the student analyzes P50 values as well as mean elevation and rainforest occupancy rates for New Caledonian woody species.
Which choice best describes the extent to which the student's hypothesis is supported by data from the table?
AAlthough the data indicate that species' vulnerability to xylem embolisms varies within a relatively narrow range, their rainforest occupancy rates and elevation distributions vary much more widely; the hypothesis is therefore not supported.
BThe data suggest a pattern in which species with enhanced tolerance of water stress are generally found at higher elevations and have higher rainforest occupancy, a relationship that holds across the majority of species examined; the hypothesis is therefore strongly supported.
CThe data indicate that compared with Zygogynum crassifolium, which has the lowest rainforest occupancy rate and occurs at the lowest mean elevation, Paracryphia alticola, which has the highest rainforest occupancy rate and occurs at the highest mean elevation, is more vulnerable to water stress; the hypothesis is therefore strongly supported.
DAlthough the data suggest a pattern in which species' resistance to xylem embolisms tends to increase with decreasing elevation and rainforest occupancy, Hedycarya parvifolia is an exception to this trend; the hypothesis is therefore moderately supported.
正确答案：D
解题思路
老师暂未填写解题思路。