The Solar System - TOEFL Reading Practice Test Paper with Answer Key

The TOEFL test examines numerous academic avenues. However, before starting this thrilling journey, excelling in the Reading section serves as a pivotal challenge for most test-takers. But worry not! We're here to support you every step of the way! 

Engaging in practice tests emerges as one of the most efficient strategies to prepare yourself for the TOEFL assessment. These exercises closely mirror the genuine TOEFL setup, aiding in familiarizing you with the exam layout and likely question formats. 

So, let's kickstart your TOEFL preparation with the Reading Practice Test Paper focusing on the topic 'The Solar System.' This test will assist you in sharpening your ability to comprehend complex texts effectively and practice time allocation techniques for TOEFL Day!

Reading Instructions

• You have 15 minutes to read the following passage and answer all 10 questions related to it.  
• Most questions are worth 1 point, but the last question is worth more. The directions indicate how many points you will receive for that specific question. 
• The specific section/paragraphs have been provided again with the question for ease of understanding and quick solution.
• Some questions include a word or phrase that is highlighted in the question as well as in the paragraph for quick reference. 

The Solar System is the gravitationally bound system of the Sun and its orbiting celestial bodies, formed approximately 4.6 billion years ago through the gravitational collapse of a vast interstellar cloud. The Sun accounts for the overwhelming majority (99.86%) of the system's mass, while Jupiter holds most of the remaining mass. Among the inner planets—Mercury, Venus, Earth, and Mars—are terrestrial ones, predominantly composed of rock and metal. In contrast, the outer system hosts four giant planets, notably larger and more massive than their terrestrial counterparts. Jupiter and Saturn, the largest, are gas giants primarily made of hydrogen and helium, while Uranus and Neptune, the subsequent two, are ice giants, composed mainly of volatile substances like water, ammonia, and methane. All eight planets follow nearly circular orbits, aligning closely with the plane of Earth's orbit known as the ecliptic.

There exists an unspecified quantity of smaller dwarf planets and countless minor bodies within the Solar System orbiting the Sun. Among the major planets, six of the largest potential dwarf planets, as well as numerous smaller bodies, are accompanied by natural satellites, commonly referred to as "moons," reminiscent of Earth's Moon. Notably, two of these natural satellites—Ganymede orbiting Jupiter and Titan orbiting Saturn—are larger than Mercury, the smallest terrestrial planet, though less massive, and Jupiter's moon Callisto approaches Mercury's size. Each of the gas giant planets and some smaller bodies is surrounded by rings comprised of ice, dust, and moonlets. Positioned between the orbits of Mars and Jupiter, the asteroid belt hosts objects composed of rock, metal, and ice. Extending past Neptune's orbit are the Kuiper belt and scattered disc, populated by objects predominantly made of ice and rock.

In the distant regions of the Solar System, a group of minor planets known as detached objects resides. There is ongoing debate regarding the exact number of such objects. Among them, some have attained a spherical shape due to their own gravitational force, meeting the criteria for classification as dwarf planets. Astronomers generally acknowledge approximately nine objects as dwarf planets: Ceres, an asteroid; Pluto, Orcus, Haumea, Quaoar, and Makemake from the Kuiper belt; and Gonggong, Eris, and Sedna from the scattered disc. Various populations of small bodies, such as comets, centaurs, and interplanetary dust clouds, traverse freely between different regions of the Solar System.

The solar wind, characterized by a flow of charged particles emanating from the Sun, generates a bubble-like expanse within the interstellar medium known as the heliosphere. The heliopause marks the boundary where the pressure exerted by the solar wind equals the opposing pressure of the interstellar medium, extending outward to the edge of the scattered disc. Positioned at a distance roughly a thousand times farther than the heliosphere, the Oort cloud is believed to serve as the origin of long-period comets. The Solar System is situated approximately 26,000 light-years away from the central region of the Milky Way galaxy, within the Orion Arm, which hosts the majority of visible stars in the night sky. The closest stars reside within the Local Bubble, with Proxima Centauri, the nearest one, located at a distance of 4.2441 light-years.

Directions: Now answer the questions. 

Paragraph 1

The Solar System is the gravitationally bound system of the Sun and its orbiting celestial bodies, formed approximately 4.6 billion years ago through the gravitational collapse of a vast interstellar cloud. The Sun accounts for the overwhelming majority (99.86%) of the system's mass, while Jupiter holds most of the remaining mass. Among the inner planets—Mercury, Venus, Earth, and Mars—are terrestrial ones, predominantly composed of rock and metal. In contrast, the outer system hosts four giant planets, notably larger and more massive than their terrestrial counterparts. Jupiter and Saturn, the largest, are gas giants primarily made of hydrogen and helium, while Uranus and Neptune, the subsequent two, are ice giants, composed mainly of volatile substances like water, ammonia, and methane. All eight planets follow nearly circular orbits, aligning closely with the plane of Earth's orbit known as the ecliptic.

1. According to the passage, which statement accurately describes a characteristic of the Solar System?
   1. Jupiter holds the majority of the system's mass.
   2. Gas giants dominate the composition of the Solar System.
   3. The Sun accounts for the bulk of the Solar System's mass.
   4. The four inner planets are significantly larger than the terrestrial ones.

1. The term "gravitationally bound" in the paragraph is most similar in meaning to which of the following?
   1. Pulling apart
   2. Repulsed by gravity
   3. Stopped by gravity
   4. Moving together

1. Which sentence most accurately conveys the main idea of the following statement?
   
   "All eight planets have nearly circular orbits that lie near the plane of Earth's orbit, called the ecliptic."
   1. All planets orbit the Earth.
   2. The orbits of all eight planets are near the ecliptic.
   3. The ecliptic is the orbit of eight planets.
   4. The eight planets orbit in nearly circular orbits near the ecliptic.

Paragraph 3

In the distant regions of the Solar System, a group of minor planets known as detached objects resides. There is ongoing debate regarding the exact number of such objects. Among them, some have attained a spherical shape due to their own gravitational force, meeting the criteria for classification as dwarf planets. Astronomers generally acknowledge approximately nine objects as dwarf planets: Ceres, an asteroid; Pluto, Orcus, Haumea, Quaoar, and Makemake from the Kuiper belt; and Gonggong, Eris, and Sedna from the scattered disc. Various populations of small bodies, such as comets, centaurs, and interplanetary dust clouds, traverse freely between different regions of the Solar System.

1. From the paragraph discussing the objects in the Solar System, which conclusion can be drawn?
   1. The materials comprising the Solar System objects are predominantly rock and metal.
   2. Various materials make up the objects within the Solar System.
   3. The Solar System encompasses diverse types of planets.
   4. The majority of Solar System objects consist of volatile substances.

Paragraph 4

The solar wind, characterized by a flow of charged particles emanating from the Sun, generates a bubble-like expanse within the interstellar medium known as the heliosphere. The heliopause marks the boundary where the pressure exerted by the solar wind equals the opposing pressure of the interstellar medium, extending outward to the edge of the scattered disc. Positioned at a distance roughly a thousand times farther than the heliosphere, the Oort cloud is believed to serve as the origin of long-period comets. The Solar System is situated approximately 26,000 light-years away from the central region of the Milky Way galaxy, within the Orion Arm, which hosts the majority of visible stars in the night sky. The closest stars reside within the Local Bubble, with Proxima Centauri, the nearest one, located at a distance of 4.2441 light-years.

1. Based on the paragraph, which statement is inaccurate regarding the Solar System?
   1. Jupiter and Saturn, the two largest planets, are classified as gas giants.
   2. The outer system's four giant planets are significantly larger than the terrestrial ones.
   3. The orbits of the eight planets are almost circular.
   4. The Solar System is positioned 26,000 light-years away from the Milky Way galaxy's center.

1. The paragraph suggests which of the following about the minor planets situated in the outer fringes of the Solar System?
   1. Certain objects among them may not meet the criteria for dwarf planet classification.
   2. The quantity of detached objects is uncertain.
   3. Astronomers do not unanimously agree on the count of dwarf planets.
   4. These objects consist predominantly of ice and rock.

1. What is the purpose of the author mentioning the solar wind in the passage?
   1. To detail the composition of the major planets.
   2. To elucidate the formation of the heliosphere.
   3. To outline the various categories of objects in the Solar System.
   4. To clarify the position of the Solar System within the Milky Way galaxy.

1. The term "interstellar" in the passage is most similar in meaning to which of the following?
   1. Internal
   2. Outer space
   3. Between stars
   4. Extraterrestrial

Paragraph 3

In the distant regions of the Solar System, a group of minor planets known as detached objects resides. (A) There is ongoing debate regarding the exact number of such objects. (B) Among them, some have attained a spherical shape due to their own gravitational force, meeting the criteria for classification as dwarf planets. (C) Astronomers generally acknowledge approximately nine objects as dwarf planets: Ceres, an asteroid; Pluto, Orcus, Haumea, Quaoar, and Makemake from the Kuiper belt; and Gonggong, Eris, and Sedna from the scattered disc. (D) Various populations of small bodies, such as comets, centaurs, and interplanetary dust clouds, traverse freely between different regions of the Solar System.

1. Directions: Examine the segment of the text shown above. The letters (A), (B), (C), and (D) denote possible insertion points for the following sentence.
   
   Astronomers have identified nine objects as dwarf planets in the Solar System.
   
   Where would the sentence best fit?
   1. Choice A
   2. Choice B
   3. Choice C
   4. Choice D

1. Directions: Below is an introductory sentence for summarizing the passage. You need to choose three answer choices that represent the most significant ideas in the passage to complete the summary. Some answer choices are irrelevant or minor ideas not discussed in the passage. This question carries a weight of 2 points.
   
   The Solar System is a complex and vast system of the Sun and the objects that orbit it.
   

   Answer Choices

   1. Long-period comets might originate from the Oort cloud.
   2. Most of the Solar System's mass resides within the Sun.
   3. The inner four planets are terrestrial, while the outer four consist of gas giants or ice giants.
   4. The heliosphere forms from the solar wind, creating a region of interplanetary medium.
   5. Positioned 26,000 light-years from the Milky Way's center, the Solar System resides.
   6. Rocks, metals, and ice predominantly make up the objects within the asteroid belt.

Answer Key with Explanation for TOEFL Reading Passage - The Solar System

1. Answer: C

Explanation: The correct answer is Option C. The Sun accounts for the bulk of the Solar System's mass. The passage explicitly states that "The Sun accounts for the overwhelming majority (99.86%) of the system's mass." This indicates that the majority of the Solar System's mass is concentrated within the Sun. Therefore, option C accurately describes a characteristic of the Solar System as presented in the passage.

2. Answer: D

Explanation: The correct answer is Option D) Moving together. In the passage, the term "gravitationally bound" refers to the system of the Sun and its orbiting celestial bodies being held together by the force of gravity. This suggests that these objects are connected and move together due to gravitational attraction. Therefore, option D, "Moving together," best captures the meaning of "gravitationally bound" as described in the passage.

3. Answer: D

Explanation: The correct answer is Option D) The eight planets orbit in nearly circular orbits near the ecliptic. This option accurately captures the main idea of the statement by emphasizing that all eight planets in the Solar System follow nearly circular orbits close to the ecliptic plane, which is the path of Earth's orbit around the Sun. The other options either misinterpret the statement or do not fully convey its meaning.

4. Answer: B

Explanation: The correct answer is Option B) Various materials make up the objects within the Solar System. The paragraph discusses the diverse composition of objects within the Solar System, including planets, dwarf planets, moons, and smaller bodies like asteroids and comets. It mentions the presence of rocky and metallic objects, as well as volatile substances like water, ammonia, and methane. Therefore, the conclusion that various materials make up the objects within the Solar System is most supported by the information provided in the passage.

5. Answer: D

Explanation: The correct answer is Option D) The Solar System is positioned 26,000 light-years away from the Milky Way galaxy's center. This statement is inaccurate based on the information provided in the passage. The passage does not mention the specific distance of the Solar System from the Milky Way galaxy's center. It discusses characteristics of the Solar System itself, such as the composition of planets, their orbits, and the presence of other celestial bodies, but it does not provide information about its exact position within the galaxy. Therefore, option D cannot be confirmed based on the passage.

6. Answer: A

Explanation: The Correct answer is Option A) Certain objects among them may not meet the criteria for dwarf planet classification. The paragraph mentions that there is ongoing debate about the exact number of detached objects and that some of them have attained a spherical shape due to their own gravitational force, meeting the criteria for classification as dwarf planets. This suggests that not all objects among them may meet the criteria for dwarf planet classification, as indicated in option A. Options B and C are partially supported by the paragraph but do not directly relate to the characteristics of the minor planets. Option D is not explicitly mentioned in the paragraph.

7. Answer: B

Explanation: The correct answer is Option B) To elucidate the formation of the heliosphere. The passage discusses how the solar wind, a stream of charged particles emanating from the Sun, creates a bubble-like expanse within the interstellar medium known as the heliosphere. Therefore, the mention of the solar wind serves to explain the formation and characteristics of the heliosphere, making option B the most relevant choice. The other options do not accurately reflect the purpose of mentioning the solar wind as described in the passage.

8. Answer: C

Explanation: The correct answer is Option C) Between stars. The term "interstellar" typically refers to the space between stars. In the passage, it is used in the context of the interstellar medium, which is the material that exists in the space between stars. Therefore, option C, "Between stars," is the most similar in meaning to the term "interstellar" as used in the passage.

9. Answer: C

Explanation: The sentence "Astronomers have identified nine objects as dwarf planets in the Solar System." would best fit Choice C. This sentence provides additional information about the dwarf planets mentioned in choice C, which include Ceres, Pluto, Orcus, Haumea, Quaoar, Makemake, Gonggong, Eris, and Sedna. Therefore, it logically follows the mention of these objects and aligns with the context provided in choice C.

10. Answer: B, C, D

Explanation: This is a Prose Summary question. It is completed correctly below.

The correct choices are B, D, and E. Choices A, C, and F are therefore incorrect.

Option B: This choice highlights a fundamental aspect of the Solar System's composition, emphasizing that the Sun contains the vast majority of its mass, as mentioned in the passage. The passage explicitly states, "The Sun accounts for the overwhelming majority (99.86%) of the system's mass," supporting this choice as a significant idea.

Option C: This choice delineates the distinction between the inner and outer planets based on their composition, which is a key aspect of the Solar System discussed in the passage. The passage specifies that the four inner planets (Mercury, Venus, Earth, and Mars) are terrestrial, while the outer planets (Jupiter, Saturn, Uranus, and Neptune) are gas giants or ice giants, supporting this choice as a significant idea.

Option D: This choice addresses the formation of the heliosphere, which is crucial for understanding the boundary of the Solar System and its interaction with the surrounding interstellar medium. The passage explains how the solar wind generates the heliosphere, marking the boundary where the pressure from the solar wind equals the opposing pressure of the interstellar medium, supporting this choice as a significant idea.

Option A: While the Oort cloud is mentioned in the passage as a source for long-period comets, it is not among the most significant ideas discussed in the introductory sentence. The focus of the introductory sentence should be on broader concepts that encompass the entirety of the Solar System, rather than specific details about comet origins.

Option E: While the position of the Solar System within the Milky Way galaxy is mentioned in the passage, it is not as central to the overall theme as other concepts such as the composition of the Solar System and the formation of its boundary. The introductory sentence should prioritize summarizing key aspects of the Solar System's structure and characteristics, rather than specific details about its location within the Milky Way.

Option F: While the composition of objects within the asteroid belt is mentioned in the passage, it is a relatively minor detail compared to other overarching themes such as the composition of planets, formation of the heliosphere, and mass distribution within the Solar System. The introductory sentence should focus on summarizing the most significant and broadly applicable ideas discussed in the passage, rather than minor details about specific regions within the Solar System.

Now that you’ve mastered the Reading Section with this test on ‘The Solar System’, are you ready to take your TOEFL preparation to the next level? Try some more of our tailored practice tests and build your confidence for TOEFL day. Don’t forget to share your thoughts in the comments!