Reading Practice Test - 3 | Practice Tests for TOEFL PDF Download

The Formation of the Grand Canyon

Passage 1
The Grand Canyon, located in the state of Arizona, is one of the most recognized natural wonders in the world. Its vastness, beauty, and geological significance attract millions of visitors each year. The canyon’s formation, however, is the result of millions of years of natural processes, involving erosion, tectonic activity, and the flow of the Colorado River. Though the exact timeline is still debated, scientists believe the canyon began forming about 5 to 6 million years ago when the Colorado River started cutting through layers of rock that had been deposited over millions of years.

Passage 2
Before the Colorado River carved out the Grand Canyon, the area was covered by a shallow sea, which gradually receded. As the sea withdrew, it left behind thick layers of sediment, which would later become the rock layers seen in the canyon’s walls today. The region was also subject to volcanic activity, with lava flows and ash deposits adding another layer of complexity to the geological landscape. These layers of rock, some more than 2 billion years old, contain a history of the Earth’s changing environment.

Passage 3
The process of erosion, combined with the power of the Colorado River, has played a central role in the canyon’s formation. As the river flowed over the land, it picked up sediment and debris, gradually wearing away the rock beneath it. Over time, the river deepened and widened the canyon, creating the dramatic cliffs and rock formations visible today. The force of the river, combined with wind, rain, and freezing temperatures, continues to shape and reshape the canyon even now.

Passage 4
The geological history of the Grand Canyon also includes significant tectonic activity. The region has experienced considerable uplift due to the movement of tectonic plates. This uplift has caused the rock layers that formed at the bottom of the sea to rise and become exposed to the elements. The combination of tectonic activity, erosion, and the Colorado River’s flow created the distinctive layers of sedimentary rock that give the canyon its unique appearance.

Passage 5
Today, the Grand Canyon is not only a geological marvel but also a rich habitat for many species of plants and animals. Its diverse ecosystems range from desert to forest, and it contains several unique species that are found nowhere else on Earth. Despite its harsh conditions, the canyon supports a variety of life, and scientists continue to study its ecosystems and geology to better understand the Earth’s past.

Q1. Which of the following is NOT mentioned in paragraph 1 as a factor in the Grand Canyon’s formation?
(a) The Colorado River’s flow
(b) Tectonic activity
(c) Volcanic eruptions
(d) Erosion by wind and rain

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Q2. What is the author’s purpose in mentioning the age of the rock layers?
(a) To explain how volcanic activity contributed to the canyon's formation
(b) To show the variety of rocks in the Grand Canyon
(c) To emphasize the long geological history of the region
(d) To describe the geological processes that created the canyon’s current appearance

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Q3. According to paragraph 3, which of the following contributed to the shaping of the Grand Canyon? Select TWO answer choices.
(a) Volcanic activity
(b) Erosion by the Colorado River
(c) Freezing temperatures
(d) Shifting of tectonic plates

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Q4. What is the main purpose of paragraph 4?
(a) To describe the relationship between volcanic activity and the Grand Canyon’s formation
(b) To explain how tectonic activity influenced the Grand Canyon’s geology
(c) To give an overview of the natural forces that shaped the Grand Canyon
(d) To emphasize the importance of the Colorado River in forming the canyon

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Q5. Why is the Grand Canyon considered a rich habitat for many species?
(a) Because of its diverse ecosystems
(b) Because of its volcanic soil
(c) Because it has a mild climate
(d) Because it is home to unique rock formations

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Q6. The word “uplift” in paragraph 4 is closest in meaning to
(a) Gradual sinking
(b) Rising or lifting
(c) Shrinking
(d) Leveling

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Q7. What is the primary effect of tectonic activity on the Grand Canyon?
(a) It created volcanic lava flows in the canyon.
(b) It caused rock layers to become exposed.
(c) It slowed the process of erosion.
(d) It allowed the Colorado River to flow freely through the canyon.

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Q8. Which of the following best summarizes the content of paragraph 3?
(a) The Grand Canyon is the result of volcanic activity and tectonic movement.
(b) Erosion by the Colorado River, combined with natural forces like wind and rain, shaped the canyon.
(c) Wind and rain are the main factors responsible for the Grand Canyon’s formation.
(d) The Grand Canyon’s formation was solely due to the movement of the Colorado River.

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Q9. In paragraph 2, the sentence “As the sea withdrew, it left behind thick layers of sediment, which would later become the rock layers seen in the canyon’s walls today” suggests that
(a) The rock layers formed after volcanic activity in the region.
(b) The sedimentary layers were deposited gradually over time.
(c) The ocean water was responsible for the creation of the canyon’s rock formations.
(d) The rock layers formed before the sea existed in the region.

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Q10. Directions: An introductory sentence for a brief summary of the passage is provided below. Complete the summary by selecting the THREE answer choices that express the most important ideas in the passage. Some sentences do not belong in the summary because they express ideas that are not presented in the passage or are minor ideas in the passage.
The Grand Canyon’s geological history is the result of various natural forces acting over millions of years.
(a) The Grand Canyon was primarily formed by volcanic eruptions that added layers of rock to the region.
(b) Erosion by the Colorado River, combined with tectonic activity and natural weathering, played key roles in forming the canyon.
(c) The canyon’s unique layers of rock are the result of both the movement of tectonic plates and the deposition of sediment.
(d) The Grand Canyon is a rich habitat for many species, making it an important site for biodiversity research.
(e) The region was originally covered by a sea, and the land gradually rose through tectonic activity to form the canyon’s present structure.
(f) The Grand Canyon’s geological features have remained unchanged for millions of years, despite natural forces.

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