What this section covers: Physical science, Biological science.
15 free practice questions
Click an answer: you see at once whether it is right, with the explanation.
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Question 1Which cell structure is responsible for making most of a cell's ATP, its main energy-carrying molecule?
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Answer: C — Mitochondrion.
Mitochondria carry out cellular respiration, which uses the chemical energy in glucose and other nutrients to make ATP; that is why they are called the powerhouses of the cell. Ribosomes build proteins and the nucleus holds the DNA.
Checked against: Official ASVAB — General Science (GS): knowledge of physical and biological sciences; OpenStax Biology 2e, 4.3 Eukaryotic Cells (Mitochondria)
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Question 2In a DNA double helix, the base adenine (A) on one strand always pairs with which base on the opposite strand?
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Answer: A — Thymine (T).
DNA base pairing is complementary: A pairs with T and G pairs with C. Uracil replaces thymine in RNA, not in DNA.
Checked against: Official ASVAB — General Science (GS): knowledge of physical and biological sciences; OpenStax Biology 2e, 14.2 DNA Structure and Sequencing
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Question 3Which gas do green plants release into the air as a product of photosynthesis?
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Answer: D — Oxygen.
Photosynthesis uses light energy, carbon dioxide and water to make carbohydrates, and it releases oxygen. Carbon dioxide is taken in, not released, by photosynthesis.
Checked against: Official ASVAB — General Science (GS): knowledge of physical and biological sciences; OpenStax Biology 2e, 8.1 Overview of Photosynthesis
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Question 4Two pea plants that are both heterozygous for seed color (Yy, where yellow Y is dominant over green y) are crossed. What fraction of the offspring is expected to have green seeds?
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Answer: B — 1/4.
The cross Yy × Yy gives genotypes in a 1:2:1 ratio (YY : Yy : yy). Only yy plants show the recessive green color, so 1/4 of the offspring are expected to be green; the other 3/4 are yellow.
Checked against: Official ASVAB — General Science (GS): knowledge of physical and biological sciences; OpenStax Biology 2e, 12.2 Characteristics and Traits (monohybrid cross, 1:2:1 ratio)
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Question 5Oxygen-poor blood returning from the body through the venae cavae enters which chamber of the human heart first?
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Answer: C — Right atrium.
The right atrium receives deoxygenated blood from the superior and inferior venae cavae; it then passes to the right ventricle, which pumps it to the lungs. The left atrium receives oxygen-rich blood coming back from the lungs.
Checked against: Official ASVAB — General Science (GS): knowledge of physical and biological sciences; OpenStax Biology 2e, 40.3 Mammalian Heart and Blood Vessels
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Question 6In the food chain grass → grasshopper → frog → snake, which organism is the primary consumer?
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Answer: D — Grasshopper.
Primary consumers are the herbivores that eat the primary producers. The grass is the producer, the grasshopper that eats it is the primary consumer, the frog is a secondary consumer and the snake a tertiary consumer.
Checked against: Official ASVAB — General Science (GS): knowledge of physical and biological sciences; OpenStax Biology 2e, 46.1 Ecology of Ecosystems (food chains)
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Question 7Proteins are long chains built from which smaller units (monomers)?
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Answer: A — Amino acids.
Amino acids are the monomers that make up proteins. Nucleotides build nucleic acids such as DNA, simple sugars build carbohydrates, and fatty acids are parts of lipids.
Checked against: Official ASVAB — General Science (GS): knowledge of physical and biological sciences; OpenStax Biology 2e, 3.4 Proteins (Amino Acids)
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Question 8A net force acts on a 10-kilogram cart and gives it an acceleration of 2 meters per second squared. What is the size of the net force?
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Answer: C — 20 newtons.
Newton's second law states F = m × a, so F = 10 kg × 2 m/s² = 20 newtons. Dividing (10 ÷ 2 = 5) or adding (10 + 2 = 12) the numbers does not follow the law.
Checked against: Official ASVAB — General Science (GS): knowledge of physical and biological sciences; OpenStax College Physics 2e, 4.3 Newton's Second Law of Motion
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Question 9A toolbox has a mass of 12 kilograms on Earth. Gravity on the Moon is about one-sixth as strong as on Earth. What is the toolbox's mass on the Moon?
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Answer: B — 12 kilograms.
Mass is the amount of matter in an object and does not change from place to place; weight is the gravitational force and does change. The toolbox would weigh about one-sixth as much on the Moon, but its mass stays 12 kilograms.
Checked against: Official ASVAB — General Science (GS): knowledge of physical and biological sciences; OpenStax College Physics 2e, 4.3 Newton's Second Law of Motion (Mass and Weight)
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Question 10What identifies an atom as a particular element, such as carbon or oxygen?
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Answer: B — The number of protons in its nucleus.
The number of protons in the nucleus is the atomic number, and it defines the element: every atom with six protons is carbon. Atoms of one element can have different numbers of neutrons (isotopes) and can gain or lose electrons (ions).
Checked against: Official ASVAB — General Science (GS): knowledge of physical and biological sciences; OpenStax Chemistry 2e, 2.3 Atomic Structure and Symbolism
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Question 11Which of these solutions is the most acidic?
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Answer: D — A solution with a pH of 2.
On the pH scale, 7 is neutral, values below 7 are acidic and values above 7 are basic. The lower the pH, the higher the hydronium ion concentration, so pH 2 is the most acidic of the four.
Checked against: Official ASVAB — General Science (GS): knowledge of physical and biological sciences; OpenStax Chemistry 2e, 14.2 pH and pOH
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Question 12A piece of dry ice (solid carbon dioxide) left at room temperature slowly disappears without ever forming a liquid. What is this change of state called?
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Answer: B — Sublimation.
Sublimation is the direct change from solid to gas, skipping the liquid state; dry ice is the textbook example. Deposition is the reverse (gas to solid), evaporation is liquid to gas and condensation is gas to liquid.
Checked against: Official ASVAB — General Science (GS): knowledge of physical and biological sciences; OpenStax Chemistry 2e, 10.3 Phase Transitions (Sublimation and Deposition)
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Question 13Energy from the Sun reaches Earth through the near-empty space between them. By which method of heat transfer does it travel?
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Answer: C — Radiation.
Conduction and convection both need matter to carry the heat, and the space between the Sun and Earth is largely empty, so the energy arrives by radiation (electromagnetic waves). Insulation slows heat transfer; it is not a way of transferring heat.
Checked against: Official ASVAB — General Science (GS): knowledge of physical and biological sciences; OpenStax College Physics 2e, 14.7 Radiation
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Question 14What is the main cause of Earth's seasons?
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Answer: A — The tilt of Earth's axis.
The seasons are caused by the 23.5° tilt of Earth's axis, which changes how directly sunlight strikes each hemisphere and how long the days are. If distance were the cause, both hemispheres would have summer at the same time, but their seasons are opposite.
Checked against: Official ASVAB — General Science (GS): knowledge of physical and biological sciences; OpenStax Astronomy 2e, 4.2 The Seasons
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Question 15Basalt forms when lava from a volcano cools and hardens. Rock formed by cooling from a molten state is called
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Answer: C — igneous rock..
Igneous rock is any rock that has cooled from a molten state, so all volcanic rock, including basalt and granite, is igneous. Sedimentary rock forms from deposited and compacted particles, and metamorphic rock is rock changed by heat and pressure without melting.
Checked against: Official ASVAB — General Science (GS): knowledge of physical and biological sciences; OpenStax Astronomy 2e, 8.2 Earth's Crust (Composition of the Crust)
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