Question 79
(Multiple Choice)
Refer to the following information to answer the next few questions.
Researchers decided to test the hypothesis that if the 2-m tall Polytrichum gametophyte-sporophyte plants had acted as a physical buffer,then they would have reduced water's ability to erode the soil and carry away its nitrogen.They began with four equal-sized areas where Polytrichum mosses grew to a height of 2 m above the soil surface.One of the four areas was not modified.In the second area,the mosses were trimmed to a height of 1 m above the soil surface.In the third area,the mosses were trimmed to a height of 0.5 m above the soil surface.In the fourth area,the mosses were trimmed all the way to the ground,leaving only the rhizoids.Water,simulating rainfall,was then added in a controlled fashion to all plots over the course of one year.The figure below presents four graphs that depict potential results of this experiment.
-The 2-m height attainable by Polytrichum moss is at the upper end of the size range reached by mosses.What accounts for the relative height of Polytrichum?
A)the cuticle that is found along the ridges of "leaves"
B)"leaves" that are more than one cell layer thick
C)high humidity of surrounding air that provides support against gravity
D)reduced size, mass, and persistence of the sporophytes that allows gametophores to grow taller
E)the presence of conducting tissues in the "stem"
Answer