Source: Revised GRE PDF 2nd Ed. Section 3; #13 (p. 55)


According to the passage, which of the following

Geese can often be seen grazing in coastal salt marshes. Unfortunately, their intense grazing removes the grassy covering, exposing marsh sediment; this increases evaporation, which in turn increases salt concentration in marsh sediments. Because of this increased concentration, regrowth of plants is minimal, leading to increased erosion, which leads to a decrease in the fertile topsoil, leading to even less regrowth. In time, the salt marsh becomes a mudflat. This process challenges one of the most widely held beliefs about the dynamics of salt-marsh ecosystems: supposedly, consumers such as geese do not play a large role in controlling the productivity of marsh systems. Rather, the standard view claims, marshes are controlled by bottom-up factors, such as nutrients and physical factors. According to the passage, which of the following is a widely held belief about geese? They are not often seen grazing in coastal salt marshes., They are not the primary consumers in salt-marsh ecosystems., They play only a minor role in the productivity of salt-marsh ecosystems., They are the primary determinants of which resources will thrive in coastal salt marshes., They control the productivity of salt-marsh ecosystems through a bottom-up process.

1 Explanation


Gravatar Chris Lele, Magoosh Tutor

Sep 21, 2012 • Comment

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