Which choice best describes the extent to which the student’s hypothe… | Verbal SAT Question

Verbal·Information and Ideas·Command of Evidence

easy

P50 Value, Mean Elevation, and Rainforest Occupancy for Five New Caledonian Woody Species

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?

Although 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.

The 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.

The data indicate that compared with Zygogynum crassifolium, which has the lowest rainforest occupancy rate and occupies the lowest elevations, the other species are found at higher elevations and have higher rainforest occupancy rates; the hypothesis is therefore strongly supported.

The data show a positive correlation between tolerance of water stress and mean elevation and a negative correlation between tolerance of water stress and rainforest occupancy; the hypothesis is therefore only partially supported.