SCIENCE 9 REVIEWER

QUESTION 11. Which layer of the Earth is the thinnest compared with the mantle and the core?

Choose one answer

A. Asthenosphere B. Mantle C. Crust D. Outer core

QUESTION 22. Why do scientists use a scale when drawing the layers of Earth's interior?

Choose one answer

A. To make all Earth's layers appear equal in thickness B. To represent very large actual measurements using smaller proportional measurements C. To change the actual thickness of Earth's layers D. To make the drawing more colorful and attractive.

QUESTION 33. The outer core is approximately 2,250 km thick. If the scale is 1 cm = 500 km, how thick should it be in the drawing?

Choose one answer

A. 2.25 cm B. 4.5 cm C. 5.8 cm D. 11.25 cm

QUESTION 44. The lithosphere is approximately 100 km thick. Using a scale of 1 cm = 500 km, what measurement should be used in the scale drawing?

Choose one answer

A. 0.2 cm B. 0.5 cm C. 2.0 cm D. 5.0 cm

QUESTION 55. Consider the following approximate thicknesses:
• Crust – 35 km
• Mantle – 2,900 km
• Outer core – 2,250 km
• Inner core – 1,220 km
Which arrangement correctly shows these layers from thickest to thinnest?

Choose one answer

A. Mantle → Outer Core → Inner Core → Crust B. Outer Core → Mantle → Inner Core → Crust C. Mantle → Inner Core → Outer Core → Crust D. Crust → Inner Core → Outer Core → Mantle

QUESTION 66. A student uses a scale of 1 cm = 500 km and records the following:
• Mantle = 4.5 cm
• Outer Core = 5.8 cm
• Inner Core = 2.4 cm
What error did the student make?

Choose one answer

A. The inner core should be the thickest layer. B. The measurements for the mantle and outer core were interchanged. C. The outer core should be thinner than the crust. D. All three measurements are correct.

QUESTION 77. A student wants to make a scale drawing on bond paper that clearly shows the differences in thickness among Earth's layers. Which scale would be most appropriate based on the activity in the lesson?

Choose one answer

A. 1 cm = 10 km B. 1 cm = 100 km C. 1 cm = 500 km D. 1 cm = 10,000 km

QUESTION 88. A student uses a scale of 1 cm = 1,000 km but draws the crust as 1 cm thick and the mantle as 2.9 cm thick. Which evaluation is most accurate?

Choose one answer

A. The drawing is correct because every layer should be easy to see. B. The crust is greatly exaggerated and should instead appear as a very thin line. C. The mantle should be thinner than the crust. D. Both layers should be drawn with equal thickness.

QUESTION 99. Which Solar System object is often described as a “dirty snowball” because it is made largely of ice, dust, and gas?

Choose one answer

A. Asteroid B. Meteoroid C. Comet D. Dwarf planet

QUESTION 1010. Why does a comet become more noticeable when it approaches the Sun?

Choose one answer

A. It changes into a planet. B. Its icy materials are heated, producing a visible tail. C. It enters Earth's atmosphere. D. Its rocky surface turns into metal.

QUESTION 1111. Astronomers observe an irregular object composed mainly of rock and metal located between Mars and Jupiter. What is the object most likely to be?

Choose one answer

A. Comet B. Asteroid C. Dwarf planet D. Meteor

QUESTION 1212. A small rocky object is moving through space. It enters Earth's atmosphere and glows, and a piece eventually reaches the ground. Which sequence correctly names the object during these stages?

Choose one answer

A. Meteor → Meteoroid → Meteorite B. Meteorite → Meteor → Meteoroid C. Meteoroid → Meteor → Meteorite D. Meteoroid → Meteorite → Meteor

QUESTION 1313. An object orbits the Sun and is massive enough to become nearly round, but it shares its orbital neighborhood with other objects. How should this object be classified?

Choose one answer

A. Asteroid B. Comet C. Dwarf planet D. Meteorite

QUESTION 1414. Two celestial bodies are observed.
Object X: Mostly rock and metal, irregular in shape, and found mainly between Mars and Jupiter.
Object Y: Contains ice and dust and develops a tail when approaching the Sun.
Which identification is correct?

Choose one answer

A. X is a comet; Y is an asteroid. B. X is an asteroid; Y is a comet. C. X is a dwarf planet; Y is a meteoroid. D. X is a meteoroid; Y is a dwarf planet.

QUESTION 1515. A student says, “Asteroids and comets are just leftover materials, so they are not scientifically important.” Which response best evaluates this statement?

Choose one answer

A. Correct, because only planets contain information about the Solar System. B. Correct, because leftover objects have changed completely since the Solar System formed. C. Incorrect, because these objects can preserve materials from the early Solar System and provide clues about its formation. D. Incorrect, because all asteroids eventually become planets.

QUESTION 1616. Scientists discover water-bearing material in an ancient small Solar System body. Which interpretation would be most reasonable based on the lesson?

Choose one answer

A. Small celestial bodies may provide clues about materials that existed when Earth and the Solar System were forming. B. All of Earth's oceans definitely came from one asteroid. C. The object must have formed recently on Earth. D. The discovery proves that all comets contain living organisms.

QUESTION 1717. Which of the following is an example of a secondary source that students may use to gather information about meteor showers?

Choose one answer

A. Personally watching the sky without recording information B. A Science textbook or an astronomical information website C. A student's dream about a meteor shower D. A fictional movie about space

QUESTION 1818. A student wants to know when the next major meteor shower can be observed in the Philippines. Which action would best apply the research skills discussed in the lesson?

Choose one answer

A. Ask a classmate to guess the date. B. Check an official or reliable astronomical source such as PAGASA. C. Wait until a meteor randomly appears. D. Use the date from a fictional story.

QUESTION 1919. A student is preparing a table of meteor showers. Which set of information would be most useful?

Choose one answer

A. Name of shower, peak date or month, and source of the information B. Color of the sky, temperature of the classroom, and student's name C. Number of planets, names of oceans, and Moon phase only D. Distance of Earth from the Moon and names of constellations only

QUESTION 2020. The Perseid meteor shower is observed regularly around the same part of the year. Which explanation best accounts for this pattern?

Choose one answer

A. Stars begin falling toward Earth during the same month every year. B. Earth repeatedly passes through a trail of debris at a particular point in its orbit. C. The Moon produces new meteors every year. D. The atmosphere creates space rocks during certain months

QUESTION 2121. Earth passes through a cloud of small particles left along the path of a comet. What will most likely be observed?

Choose one answer

A. A new planet will form. B. Many particles may enter Earth's atmosphere and produce a meteor shower. C. The comet will immediately collide with Earth. D. Earth's orbit will permanently change.

QUESTION 2222. Two websites give different peak dates for the same meteor shower. Website A is an anonymous social-media post, while Website B is an updated astronomical page from a recognized scientific organization. Which source should receive greater weight?

Choose one answer

A. Website A because social-media posts are shorter B. Website A because it may have more reactions C. Website B because its scientific source and updated information make it more reliable D. Both sources should automatically be considered equally accurate

QUESTION 2323. A student finds that the Perseids are commonly observed in August while the Geminids are commonly observed in December. What conclusion is best supported by this pattern?

Choose one answer

A. Meteor showers can occur at predictable times of the year. B. Meteor showers happen only once. C. Meteor showers are completely random. D. Meteor showers depend only on daily weather conditions.

QUESTION 2424. A diagram shows Earth's orbit crossing a trail of comet debris at one particular location. Earth completes its orbit and returns to that location the following year. What does the diagram best explain?

Choose one answer

A. Why comets become planets B. Why meteor showers can recur annually C. Why the Sun changes position every year D. Why the Moon produces meteoroids

QUESTION 2525. After comparing information from a science textbook, a reliable astronomical website, and an annual astronomical calendar, a student concludes that meteor showers are predictable events. Which statement provides the strongest scientific justification for this conclusion?

Choose one answer

A. Meteor showers are predictable because people have traditionally made wishes on shooting stars. B. Meteor showers happen whenever the weather is clear. C. Meteor showers recur because Earth's regular orbit brings it through particular debris trails at similar times each year. D. Meteor showers occur because stars periodically fall toward Earth.