Earth and space

Rift valleys can form when fractures in Earth’s crust widen. The valley walls slowly move at a rate of only a few millimeters a year. Which of these best describes the type of tectonic activity that forms rift valleys?

• Rift valleys form where a continental plate moves under an oceanic plate.

• Rift valleys form where a plate slides horizontally past another plate.

• Rift valleys form where two plates move away from each other.

• Rift valleys form where an oceanic plate moves under another oceanic plate.

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In November 2013 an object orbiting the sun seemed to disappear behind the sun. When a satellite did not detect the object, astronomers thought that the object had been destroyed when it passed close to the sun. However, when another satellite detected a small, bright object with a fan-shaped tail, astronomers proposed that the object was not destroyed.

What type of object were astronomers most likely observing?

• A comet

• An asteroid

• A meteor

• A nebula

The satellite image below shows a portion of the Namib Desert in Africa. This is an ancient, sandy desert with dunes that can be up to 305 m tall. The Namib Desert extends inland from the Atlantic Ocean between 80 km and 200 km and receives only 5 mm to 76 mm of rain each year.

A satellite picture of this same area taken weeks before shows that the shape and location of some sand dunes have changed. Which of these most likely caused the changes in the dunes?

• Ocean waves

• Flowing rivers

• Blowing wind

• Crustal uplift

Students in a science class in Marfa, Texas, made a poster with a diagram to represent a seasonal change in the Northern Hemisphere.

Which statement best describes conditions for Earth at Position 1 in the diagram?

• There are an equal number of hours of daylight and nighttime in the Northern Hemisphere, and the North Pole is tilted away from the sun.

• The Northern Hemisphere has the fewest hours of daylight, and Earth’s axis does not tilt at this position.

• There are an equal number of hours of daylight and nighttime in the Northern Hemisphere because Earth’s axis is not tilted in this position.

• The Northern Hemisphere has the fewest hours of daylight, and the North Pole is tilted away from the sun.

Based on the map, volcanic activity would most likely be found at —

• Location W

• Location X

• Location Y

• Location Z

Two friends want to go for a night hike when there is a full moon in July.

If there is a third-quarter moon on July 2, what is the approximate date of the next full moon?

• July 9

• July 16

• July 23

• July 30

In 2011, Typhoon Nesat struck the Philippines and caused widespread flooding. After hitting the Philippines, Typhoon Nesat was predicted to hit the large city of Hanoi, Vietnam.

If Typhoon Nesat had continued along the same path, which development would most likely have reduced its strength before it hit Hanoi?

• The formation of a low-pressure area south of Bangkok

• The formation of a high-pressure area south of Bangkok

• Cool water moving into the sea east of Hanoi

• Warm water moving into the sea east of Hanoi

Barnard’s Star is about 5.9 light-years from the sun. The star has an approximate temperature of 2,800 K.

Based on the diagram, what spectral class does Barnard’s Star belong to?

• Spectral class O

• Spectral class B

• Spectral class A

• Spectral class M