ASVAB Study GuideGeneral Science Practice Test 10
Tap an answer to check it instantly and read the explanation. 10 questions: 3 easy, 4 medium and 3 hard.
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Question 1 easy
Modern humans evolved during which geological era?
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Correct answer: C — Cenozoic era
The Cenozoic era is the current geological era, covering the period from 66 million years ago to the present, during which mammals and humans evolved.
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Question 2 easy
Which gas is the second most abundant component of Earth's atmosphere by volume?
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Correct answer: B — Oxygen
Nitrogen makes up about 78% of Earth's atmosphere, while oxygen is the second most abundant gas, making up approximately 21%.
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Question 3 easy
Energy is generated in the core of stars primarily through the fusion of which element into helium?
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Correct answer: C — Hydrogen
Stars like the Sun generate energy via nuclear fusion, where hydrogen nuclei fuse together under extreme pressure and temperature to form helium.
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Question 4 medium
Which of the following solar system planets is classified as a gas giant rather than a terrestrial planet?
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Correct answer: C — Jupiter
Mercury, Venus, Earth, and Mars are rocky terrestrial planets, whereas Jupiter and Saturn are gas giants.
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Question 5 medium
Relative age dating of rock layers primarily relies on which geological principle?
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Correct answer: B — Determining the position of rock layers using the law of superposition.
Relative dating uses principles like the Law of Superposition (undeformed sedimentary layers are older at the bottom and younger at the top), unlike absolute radiometric dating which measures radioactive decay.
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Question 6 medium
What primary factor causes Earth to experience changing seasons throughout its orbit around the Sun?
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Correct answer: B — The tilt of Earth's rotational axis relative to its orbital plane
Earth's seasons are caused by its 23.5-degree axial tilt as it revolves around the Sun, which causes different hemispheres to receive varying amounts of solar intensity and daylight hours.
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Question 7 medium
The underground point where an earthquake originates and seismic energy is first released is known as the:
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Correct answer: B — Hypocenter (Focus)
The hypocenter (or focus) is the point within the Earth where seismic rupture begins, whereas the epicenter is the point on Earth's surface directly above the hypocenter.
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Question 8 hard
Compared to continental crust, oceanic crust is generally:
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Correct answer: B — Thinner and denser
Oceanic crust is thinner (about 3–6 miles / 5–10 km thick) and denser (composed mostly of basalt), whereas continental crust is thicker (about 20–30 miles / 30–50 km thick) and less dense (granitic).
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Question 9 hard
Why are fossils rarely found in metamorphic rocks?
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Correct answer: B — The extreme heat and pressure that form metamorphic rocks usually destroy organic remains.
Metamorphism involves intense heat and pressure that recrystallize minerals, which typically distorts or completely obliterates any fossils originally preserved in the parent rock.
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Question 10 hard
What is the estimated temperature at the boundary between Earth's outer core and inner core?
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Correct answer: B — 9,000°F to 10,800°F (5,000°C to 6,000°C)
The temperature at Earth's inner core boundary is approximately 9,000°F to 10,800°F (about 5,000°C to 6,000°C), which is roughly as hot as the surface of the Sun.