ASVAB General Science Practice Test 6

Answer: C

Correct answer: ATP. ATP, adenosine triphosphate, stores energy in the bonds linking its phosphate groups. When the last phosphate is removed, ATP becomes ADP and releases energy that powers muscle contraction, active transport, and building molecules. Cells then recharge ADP back to ATP using energy from food. Think of ATP as rechargeable cash for the cell. DNA is a tempting distractor because it is also a famous three-letter molecule, but it stores genetic information, not usable energy.

• A: Chlorophyll is a light-absorbing pigment.
• B: Cellulose is structural plant wall material.
• C (correct): Correct: ATP transfers usable energy to cellular work, including transport and movement.
• D: DNA chiefly stores hereditary information.

Answer: D

Correct answer: Newton. Newton's second law, F = ma, defines the unit: one newton is the force that accelerates a 1-kilogram mass at 1 meter per second squared, so 1 N = 1 kg·m/s². The joule, watt and kelvin are easy to mix up because they also appear in physics problems, but they measure energy, power and temperature. A useful memory link is that the unit for force carries the name of the scientist whose laws describe force and motion.

• A: Kelvin measures thermodynamic temperature.
• B: A joule measures energy.
• C: A watt measures power.
• D (correct): A newton (N) is the SI unit for the net force that can accelerate mass, such as the force in F = ma.

Answer: B

Correct answer: The Sun. A star is a ball of hot gas that produces its own energy by nuclear fusion, and the Sun is the only such object in our solar system. It holds about 99.8% of the solar system's mass, so its gravity keeps the planets in orbit. Jupiter can be a tempting pick because it is huge and mostly hydrogen, but it is far too small to sustain fusion.

• A: The Moon is Earth’s natural satellite.
• B (correct): The Sun is the star whose gravity dominates our solar system.
• C: Jupiter is a gas-giant planet.
• D: Earth is a planet, not the central star.

Answer: D

Correct answer: Liver. Bile is made continuously by liver cells and drains into ducts. Between meals, much of it is sent to the gallbladder, which stores and concentrates it, then squeezes it into the small intestine after a fatty meal. Bile salts act like detergent, breaking large fat globules into small droplets that enzymes can attack. The gallbladder is the tempting wrong answer because it releases bile, but storing is not producing.

• A: The colon absorbs water and handles undigested residue.
• B: The gallbladder stores and concentrates bile but does not chiefly produce it.
• C: The stomach produces acid and other gastric secretions.
• D (correct): Liver cells make bile that assists fat digestion.

Answer: A

Correct answer: It is usually a somatic variant and not directly inherited. Only changes in germ-line cells, the cells that give rise to eggs or sperm, can be passed to children. Ultraviolet light damages DNA in skin cells, and a resulting mutation is copied only into the skin cells that descend from the damaged one. Such somatic changes still matter for the person, for example by contributing to skin cancer. The common misconception is that any DNA change in a parent will appear in offspring.

• A (correct): A change limited to skin tissue normally does not enter offspring’s inherited DNA.
• B: Somatic acquired DNA variation alone does not prove heredity.
• C: Skin-cell changes are somatic and not routinely transmitted by gametes.
• D: An individual somatic variant does not alter an entire population.

Answer: D

Correct answer: Systematic error; subtract 1 cm from each reading. An error that shifts every reading in the same direction by the same amount is systematic. Averaging more readings does not remove it; correcting for it does, so subtract 1 cm from each length or use an undamaged tape.

• A: The error type is right, but averaging cannot remove an error that shifts every reading by the same amount.
• B: Subtracting 1 cm would work, but an error that always pushes readings the same way is systematic, not random.
• C: Random error scatters readings both high and low, but here every reading is off by the same amount in the same direction.
• D (correct): Every reading is shifted by the same 1 cm in the same direction, so correcting each reading by that amount fixes it.

Answer: A

Correct answer: Friction supplies the activation energy needed to start the reaction. Every reaction has an activation energy, a minimum energy colliding particles need. Striking the match gives enough energy through friction to get over that barrier, and then the heat released keeps the reaction going.

• A (correct): The reaction needs an initial push over the energy barrier, and the heat from friction provides it.
• B: The energy is already stored in the chemical bonds; striking only starts the reaction.
• C: Burning releases heat, so it is exothermic; once started, it keeps itself going.
• D: Rubbing on the box does not add oxygen; it provides the heat needed to begin the reaction.

Answer: A

Correct answer: They consist of tiny liquid droplets, ice crystals, or both. A cloud is visible because these particles scatter sunlight. Water vapor is a transparent gas, so a cloud forms only when vapor condenses onto tiny particles such as dust or salt, called condensation nuclei. Low, warm clouds are mostly droplets, while high, wispy cirrus clouds are made of ice crystals. The tempting error is treating clouds as vapor, which you could never actually see.

• A (correct): Visible cloud particles are small liquid droplets, ice crystals, or a mixture.
• B: Volcanic gases can influence clouds but are not the defining constituent.
• C: Water vapor is an invisible gas; clouds become visible only after vapor condenses into droplets or ice.
• D: Clouds are collections of tiny particles, not single solid blocks.

Answer: D

Correct answer: 35°. The law of reflection says the angle of reflection equals the angle of incidence, with both measured from the normal, an imaginary line perpendicular to the surface. The key trap is the reference line: an angle measured from the mirror surface is the complement, 90° − 35° = 55°. Always check which line an angle is taken from. A ray striking straight along the normal, at 0°, bounces straight back.

• A: Seventy degrees doubles the incident angle, which is not the reflection law.
• B: Fifty-five degrees is measured from the mirror surface, not the stated normal reference.
• C: Zero degrees would be a perpendicular incident ray, unlike this 35° case.
• D (correct): The law of reflection gives equal incident and reflected angles measured from the normal.

Answer: C

Correct answer: Baking soda is stirred into vinegar and fizzes. Bubbles are only a clue. Ask where the gas came from: in baking soda and vinegar, a new gas is made when the two substances react, which is a chemical change. In the other cases the gas was already present or is the same substance in a different state.

• A: The carbon dioxide was already dissolved in the soda and is simply escaping, a physical change.
• B: Shaking traps air that was already present; no new substance forms, so the change is physical.
• C (correct): The gas is a new substance produced when the two materials react, so this is a chemical change.
• D: The bubbles are water vapor, still water in a new state, so boiling is physical.

Answer: A

Correct answer: Precise but not accurate. Precision is how closely repeated readings agree, and accuracy is how close they are to the true value. These readings differ by only 0.01 g, so they are precise, but every one is about 2.3 g too high, so the balance is not accurate. Averaging more readings will not remove this consistent offset; the balance needs calibration.

• A (correct): The readings agree closely with one another, but all sit about 2.3 g above the true 50.00 g value.
• B: The readings are far from the true value yet very close together, which is the reverse of this description.
• C: Close agreement among readings shows precision, but a consistent 2.3 g offset means the balance is not accurate.
• D: Readings that differ by only 0.01 g are highly precise, even though they miss the true value.

Answer: D

Correct answer: Frogs and humans share a more recent common ancestor than either shares with sharks. Find where branches join. Frogs and humans meet at the most recent split, sharks join them one split earlier, and lampreys join at the oldest split. Species alive today are cousins on different branches, so none is the ancestor of another.

• A: Living species are relatives on separate branches, not ancestors of one another.
• B: Modern lampreys sit on their own branch; the tree shows a shared ancestor, not lampreys as ancestors.
• C: Frogs and humans join the shark line at the same split, so sharks are equally related to both; habitat does not determine relatedness on a tree.
• D (correct): Frogs and humans join at the last split, so their shared ancestor is more recent than the one they share with sharks.

Answer: C

Correct answer: 36 m. For constant acceleration, add the distance from the starting speed and the extra from acceleration.

• A: This counts only the acceleration term, as if she had started from rest.
• B: This leaves out the one-half factor on the acceleration term, giving 20 + 32.
• C (correct): Using v0 t plus one half a t squared gives 5 × 4 + 0.5 × 2 × 16 = 20 + 16 = 36 m.
• D: This counts only the distance from the starting speed and leaves out the extra due to acceleration.

Answer: C

Correct answer: 28 J. Net work equals the total work done by all forces, which is the same as the net force times the displacement. The applied force does +48 J, while friction acts opposite the motion and does −20 J, so the total is 28 J. Using the 12 N force alone ignores friction. By the work-energy theorem, this 28 J is exactly the crate's gain in kinetic energy.

• A: Twenty joules is the magnitude of friction’s work, with its negative sign omitted.
• B: Forty-eight joules is work by the applied force alone, ignoring friction.
• C (correct): Net horizontal force is 12−5 = 7 N; net work = 7 × 4 = 28 J.
• D: Sixty-eight joules incorrectly adds opposing force magnitudes rather than subtracting them.

Answer: B

Correct answer: The first has higher richness, but evenness is lower; overall diversity depends on the metric. Species diversity has two parts. Richness is simply the number of species, and evenness describes how equally individuals are spread among those species. A site dominated by one species has low evenness even if many rare species are present. Indices such as Shannon or Simpson combine both parts in different ways, so the two wetlands might rank differently depending on the index. Do not assume more species always means more diversity.

• A: Evenness requires counts of individuals in each species; water chemistry cannot provide it.
• B (correct): Richness and evenness are distinct components of diversity.
• C: 30 species is fewer than 60.
• D: Diversity indices weight richness and evenness differently, so more species does not guarantee higher diversity on every measure.