00:00

Question 47·Medium·Text Structure and Purpose

Some historians believe the sudden abandonment of certain Ancestral Puebloan settlements in the late 1200s CE was triggered mainly by prolonged drought. Archaeologist Leehi Toffolo, however, argues that drought was only one component of a larger suite of stresses. She points to pollen data indicating that maize yields had already been declining, evidence of social conflict in neighboring regions, and signs of overhunting in surrounding forests. Taken together, she says, these factors suggest the settlements were already vulnerable; an extended drought merely delivered the decisive blow.

Which choice best describes the function of the underlined portion in the text as a whole?