The Mystery at Earth's Center

The Earth's crust…

• has a strong smell.

• is hotter than the sun.

• is thousands of miles deep.

• has been opened with powerful bombs.

Earthquakes help scientists understand…(Easy)

• how much damage happens on Earth's surface.

• the temperature of the Earth's center.

• the way Earth's center looks.

• how to open Earth's surface.

Today scientists… (Easy)

• are done studying the Earth's core.

• believe the Earth's core is no longer changing.

• have new questions about the Earth's core.

• think the inner core and outer core are the same.

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CCSS.RI.4.9

CCSS.RI.5.9

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What is the main idea of the text? (Hard)

• It is difficult for humans to study the Earth's core, but scientists use earthquake waves to learn more.

• The Earth's center was puzzling for scientists for many years until they were able to drill deep into its surface.

• There are many places in the world left to explore and one of the most fascinating places to study is the Earth's center.

• Scientists think that starting small earthquakes and recording where their waves go could help us learn more about the Earth's core.

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CCSS.RI.4.2

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CCSS.RL.6.2

Which detail best shows why studying the Earth's center is difficult? (Medium)

• "Not only is Earth's core far, far down, but as the layers go deeper, they also grow hotter." (Paragraph 4)

• "Earth's crust is made up of gigantic plates that move very slowly." (Paragraph 6)

• "The inner core is almost as big as the moon, and it's mostly made of iron. " (Paragraph 9)

• "New research hints there might be something else at the deepest part of Earth's center." (Paragraph 10)

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CCSS.RI.4.2

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CCSS.RL.4.1

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CCSS.RL.5.2

Which sentence best explains how the Earth's mantle is different from the Earth's inner core? (Medium)

• The mantle is deeper beneath the Earth's surface than the inner core.

• The mantle is a hotter temperature than the inner core's temperature.

• The mantle is made of liquid rock and the inner core is made of solid iron.

• The mantle is a mystery to scientists but they know everything about the inner core.

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CCSS.RL.2.1

CCSS.RL.4.3

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CCSS.RL.7.3

The word "expand" in paragraph 10 most closely means —(medium)

• to speed up.

• to get looser.

• to be hidden.

• to become larger.

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CCSS.RI.4.4

CCSS.RI.5.4

CCSS.RI.6.4

CCSS.RL.5.1

CCSS.RL.5.4