SAT Text Structure and Purpose

The Indus Valley Civilization, which flourished around 2500 BCE in present-day Pakistan and India, is renowned for its sophisticated urban planning. Archaeologists have uncovered evidence of grid-pattern streets, advanced drainage systems, and standardized brick sizes across multiple cities. Yet despite these technological achievements, researchers have found remarkably few monumental structures or obvious indicators of social hierarchy compared to contemporary civilizations in Egypt and Mesopotamia. This absence has led scholars to reconsider traditional assumptions about the relationship between urban complexity and centralized political power.

Which choice best states the main purpose of the text?

• ATo highlight the advanced drainage systems found in Indus Valley cities
• BTo argue that the Indus Valley Civilization was more technologically advanced than all other ancient civilizations
• CTo explain how evidence from the Indus Valley Civilization challenges conventional ideas about urban societies✓
• DTo describe the urban planning techniques used in constructing Indus Valley streets

Marine biologists studying bioluminescent organisms have made surprising discoveries about the prevalence of light production in ocean ecosystems. Researchers estimate that up to 90 percent of deep-sea species possess the ability to generate light through chemical reactions. This capability serves multiple functions: some species use bioluminescence to lure prey, others to communicate with potential mates, and still others to startle or confuse predators. The widespread nature of bioluminescence suggests that in the perpetual darkness of the deep ocean, light production has become as essential for survival as vision is in surface environments. Understanding these mechanisms could inspire new technologies in fields ranging from medical imaging to energy-efficient lighting.

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

• AIt challenges the statistical claim about bioluminescence prevalence made in the previous sentence.
• BIt overstates the importance of bioluminescence compared to other survival adaptations.
• CIt explains the specific chemical processes by which organisms generate light.
• DIt details the various purposes that support the claim about survival importance made in the following sentence.✓

For decades, historians believed that the ancient city of Troy described in Homer's Iliad was purely mythical. However, in the 1870s, archaeologist Heinrich Schliemann began excavations at a site in modern-day Turkey. His discoveries of ancient walls, artifacts, and evidence of fire damage suggested that a real city matching Troy's description had indeed existed in the location Homer specified.

Which choice best describes the overall structure of the text?

• AIt presents a longstanding belief, then describes evidence that supports that belief.
• BIt describes a traditional view, then introduces findings that challenge that view.✓
• CIt outlines competing theories about an archaeological mystery and proves one theory definitively correct.
• DIt explains why Schliemann chose to excavate in Turkey rather than in Greece.