ASVAB — All Questions

Which part of the plant cell carries out photosynthesis?

• a.Mitochondrion
• b.Chloroplast✓
• c.Ribosome
• d.Nucleus

Chloroplasts contain chlorophyll, the green pigment that captures light energy to make sugar during photosynthesis. The nucleus stores genetic material, while mitochondria release energy from food.

What is the chemical symbol for water?

• a.H2O✓
• b.O2
• c.NaCl
• d.CO2

Water is made of two hydrogen atoms bonded to one oxygen atom, giving the formula H2O. CO2 is carbon dioxide and NaCl is table salt.

Which gas do humans need to breathe in to survive?

• a.Helium
• b.Oxygen✓
• c.Carbon dioxide
• d.Nitrogen

The human respiratory system takes in oxygen, which cells use to release energy from food. Carbon dioxide is the waste gas that people breathe out.

The force that pulls objects toward the center of the Earth is called:

• a.Friction
• b.Magnetism
• c.Gravity✓
• d.Inertia

Gravity is the attractive force that pulls objects toward the Earth's center, giving them weight. Friction opposes motion between surfaces, and magnetism acts between magnetic materials.

Which planet is closest to the Sun?

• a.Mars
• b.Venus
• c.Mercury✓
• d.Earth

Mercury is the innermost planet, orbiting nearest to the Sun. Venus is second, Earth third, and Mars fourth.

What is the basic unit of heredity that carries traits from parents to offspring?

• a.Tissue
• b.Gene✓
• c.Cell
• d.Organ

A gene is a segment of DNA that carries the instructions for inherited traits. Cells, tissues, and organs are structural levels of the body, not units of heredity.

At what temperature does pure water freeze at sea level, in degrees Celsius?

• a.100 degrees
• b.-10 degrees
• c.32 degrees
• d.0 degrees✓

Pure water freezes at 0 degrees Celsius at standard sea-level pressure. That same point is 32 degrees on the Fahrenheit scale, while water boils at 100 degrees Celsius.

Which blood cells help fight infection in the body?

• a.Plasma proteins
• b.White blood cells✓
• c.Red blood cells
• d.Platelets

White blood cells are part of the immune system and defend the body against germs and infection. Red blood cells carry oxygen, and platelets help blood clot.

The process by which liquid water turns into water vapor is called:

• a.Freezing
• b.Precipitation
• c.Condensation
• d.Evaporation✓

Evaporation is the change of a liquid into a gas as molecules gain enough energy to escape the surface. Condensation is the reverse, when vapor turns back into liquid.

Which of these is an example of a chemical change?

• a.Tearing paper
• b.Water boiling
• c.Iron rusting✓
• d.Ice melting

Rusting forms a new substance, iron oxide, so it is a chemical change. Melting, boiling, and tearing are physical changes that do not create new substances.

The Richter scale is used to measure the strength of:

• a.Earthquakes✓
• b.Floods
• c.Tornadoes
• d.Hurricanes

The Richter scale measures the magnitude, or energy released, of earthquakes. Hurricanes and tornadoes are rated on different scales based on wind speed.

Which organ system is responsible for pumping blood throughout the body?

• a.Circulatory system✓
• b.Respiratory system
• c.Digestive system
• d.Nervous system

The circulatory system, centered on the heart and blood vessels, pumps blood to deliver oxygen and nutrients. The respiratory system handles breathing, and the digestive system processes food.

What type of energy is stored in a stretched rubber band?

• a.Thermal energy
• b.Sound energy
• c.Potential energy✓
• d.Kinetic energy

A stretched rubber band stores potential energy because of its position or state. When released, that stored energy converts into kinetic energy, the energy of motion.

Which part of the atom carries a negative electric charge?

• a.Electron✓
• b.Nucleus
• c.Neutron
• d.Proton

Electrons carry a negative charge and orbit the atom's nucleus. Protons carry a positive charge and neutrons have no charge, both residing in the nucleus.

Photosynthesis produces oxygen and which sugar?

• a.Lactose
• b.Glucose✓
• c.Sucrose
• d.Fructose

During photosynthesis, plants use carbon dioxide and water to make glucose and release oxygen. Glucose is the simple sugar plants use for energy and growth.

The layer of gases surrounding the Earth is called the:

• a.Atmosphere✓
• b.Lithosphere
• c.Biosphere
• d.Hydrosphere

The atmosphere is the envelope of gases held around Earth by gravity. The lithosphere is the solid crust, and the hydrosphere includes the planet's water.

Which component of blood carries oxygen to the tissues?

• a.white blood cells
• b.platelets
• c.blood plasma
• d.red blood cells✓

Red blood cells contain hemoglobin, the iron-bearing protein that binds oxygen. Platelets are involved in clotting and white cells in immune defense.

Which cell structure releases most of the energy a cell uses?

• a.the mitochondria✓
• b.the cell membrane
• c.the ribosomes
• d.the nucleus

Mitochondria carry out the reactions that convert food energy into ATP. Ribosomes build proteins and the nucleus stores genetic information.

At sea level, water boils at approximately what Fahrenheit temperature?

• a.180 degrees
• b.273 degrees
• c.100 degrees
• d.212 degrees✓

Water boils at 212 degrees Fahrenheit, which is 100 degrees Celsius. The figure 273 belongs to the Kelvin scale, where 273 K is the freezing point.

Which planet orbits closest to the sun?

• a.Jupiter
• b.Neptune
• c.Venus
• d.Mercury✓

Mercury holds the innermost orbit, with Venus next and Jupiter and Neptune far beyond Earth. Venus is the hotter planet even though it orbits farther out.

Which gas do plants take in from the air during photosynthesis?

• a.free oxygen gas
• b.nitrogen gas
• c.carbon dioxide✓
• d.hydrogen

Photosynthesis uses carbon dioxide and water to build sugar, releasing oxygen as a by-product. Plants take oxygen in for respiration, not for photosynthesis.

Which element makes up the greatest share of the Earth's crust by mass?

• a.oxygen✓
• b.silicon
• c.aluminum
• d.iron

Oxygen accounts for roughly 46 percent of the crust by mass, bound up in silicate and oxide minerals. Silicon is second at about 28 percent.

How many chromosomes are found in a normal human body cell?

• a.46✓
• b.64
• c.32
• d.23

A body cell holds 23 pairs, or 46 chromosomes. A sperm or egg cell carries half that number, 23.

Which of these animals is a vertebrate?

• a.earthworm
• b.frog✓
• c.jellyfish
• d.octopus

A vertebrate has a backbone, and a frog does. Earthworms, jellyfish, and octopuses have no internal skeleton of bone or cartilage.

Frequency is measured in which unit?

• a.hertz✓
• b.newtons
• c.watts
• d.joules

One hertz is one cycle per second. Newtons measure force, joules measure energy, and watts measure power.

About how fast does sound travel through air at room temperature?

• a.110,000 feet per second
• b.110 feet per second
• c.11,000 feet per second
• d.1,100 feet per second✓

Sound moves through air at roughly 1,100 feet per second, or about 760 miles per hour. That is why thunder lags several seconds behind the lightning flash.

Which of the following is a chemical change rather than a physical change?

• a.a rock being crushed
• b.iron rusting✓
• c.water boiling
• d.ice melting

Rusting produces a new substance, iron oxide, so it is a chemical change. Melting, boiling, and crushing change form or state without changing the substance.

A trait that appears only when an individual inherits two copies of the gene is described as

• a.environmental
• b.recessive✓
• c.acquired
• d.dominant

A recessive trait is masked whenever a dominant copy is present, so it shows only when both copies are recessive.

What causes the phases of the moon?

• a.its position relative to Earth and the sun✓
• b.changes in the moon's own brightness
• c.clouds in the Earth's own atmosphere
• d.the shadow of the Earth as it falls on it

Half the moon is lit at all times, and the phase is simply how much of that lit half faces Earth. The Earth's shadow causes a lunar eclipse, which is a separate event.

Nearly all of the Earth's weather occurs in which layer of the atmosphere?

• a.the thermosphere
• b.the stratosphere
• c.the troposphere✓
• d.the mesosphere

The troposphere is the lowest layer and holds most of the atmosphere's water vapor, so clouds and storms form there. The ozone layer sits above it in the stratosphere.

Through which of the following can sound not travel?

• a.liquid water
• b.humid air
• c.a vacuum✓
• d.solid steel

Sound is a pressure wave and needs particles to carry it, so it cannot cross a vacuum. It actually travels faster in water and steel than in air.

Which vitamin does the body make in skin exposed to sunlight?

• a.vitamin C
• b.vitamin K
• c.vitamin A
• d.vitamin D✓

Ultraviolet light converts a compound in the skin into vitamin D, which the body needs to absorb calcium.

What is the pH of a neutral solution?

• a.10
• b.7✓
• c.0
• d.14

On the 0 to 14 pH scale, 7 is neutral. Values below 7 are acidic and values above 7 are basic.

An animal that holds its body temperature steady regardless of its surroundings is called

• a.warm-blooded✓
• b.cold-blooded
• c.nocturnal
• d.invertebrate

Warm-blooded animals such as mammals and birds generate and regulate their own heat. Cold-blooded animals take on the temperature of their surroundings.

Which organ produces insulin?

• a.the pancreas✓
• b.the liver
• c.the kidneys
• d.the gall bladder

Cells in the pancreas release insulin, which lets the body's cells take up glucose from the blood.

Igneous rock is formed from

• a.cooled magma✓
• b.layers of compressed sediment
• c.existing rock under heat and pressure
• d.minerals left by evaporating water

Igneous rock solidifies from molten rock. Compressed sediment forms sedimentary rock, and heat and pressure on existing rock form metamorphic rock.

What force holds a satellite in orbit around the Earth?

• a.friction
• b.gravity✓
• c.magnetism
• d.air pressure

Gravity continuously pulls the satellite toward Earth while its forward motion carries it past, and the combination is an orbit.

What is the largest artery in the human body?

• a.the femoral
• b.the vena cava
• c.the carotid
• d.the aorta✓

The aorta leaves the left side of the heart and supplies every other artery. The vena cava is the body's largest vein, not an artery.

A solar eclipse occurs when

• a.the Earth passes between the moon and the sun
• b.the moon moves into the Earth's own shadow
• c.the moon passes between the Earth and the sun✓
• d.the sun passes behind the far side of Earth

In a solar eclipse the moon blocks the sun from part of the Earth's surface. When the moon moves into Earth's shadow instead, the result is a lunar eclipse.

Which of the following is a chemical element?

• a.bronze
• b.air
• c.helium✓
• d.water

Helium appears on the periodic table as a single kind of atom. Bronze is an alloy, water is a compound, and air is a mixture of gases.

In the human lung, gas exchange with the blood takes place in the

• a.diaphragm
• b.trachea
• c.alveoli✓
• d.bronchi

The alveoli are the tiny air sacs at the ends of the airways, where oxygen and carbon dioxide cross into and out of the blood. The bronchi and trachea only carry air.

The process by which water moves from a plant's leaves into the air is called

• a.germination
• b.precipitation
• c.condensation
• d.transpiration✓

Transpiration is evaporation through the pores of a leaf, and it pulls water upward from the roots. Condensation and precipitation are stages of the weather cycle.

On the Celsius scale, at what temperature does fresh water freeze?

• a.0 degrees✓
• b.32 degrees
• c.273 degrees
• d.100 degrees

Water freezes at 0 degrees Celsius, which is the same temperature as 32 degrees Fahrenheit.

A stretched spring holds which kind of energy?

• a.kinetic
• b.potential✓
• c.thermal
• d.electrical

Energy stored by position or deformation is potential energy. It becomes kinetic energy of motion when the spring is released.

Which part of an animal cell controls which substances enter and leave the cell?

• a.the Golgi apparatus
• b.the nuclear envelope
• c.the cell membrane✓
• d.the cell's cytoplasm

The cell membrane is a lipid bilayer that lets some molecules cross and blocks others, so it decides what a cell takes in and what it expels. The nuclear envelope tempts because it is also a membrane with pores, but it guards the DNA inside the cell rather than the cell's outer boundary.

Which cell structures link amino acids together to build proteins?

• a.the ribosomes✓
• b.the chloroplasts
• c.the chromosomes
• d.the lysosomes

Ribosomes read the messenger RNA copy of a gene and link amino acids into a chain in that order, which is why cells that export a lot of protein are packed with them. Chromosomes tempt because they store the instructions, but storing a recipe is not the same as cooking from it.

Which organ filters urea and other wastes out of the blood to form urine?

• a.the bladder
• b.the spleen
• c.the kidney✓
• d.the liver

Each kidney holds about a million nephrons that filter blood under pressure, reabsorb water and useful salts, and pass the rest out as urine. The liver tempts because it is where urea is actually made from broken-down protein, but it hands that waste to the blood for the kidneys to clear.

Two parents each carry one dominant and one recessive copy of the same gene. What fraction of their children are expected to show the recessive trait?

• a.1 in 2
• b.1 in 4✓
• c.3 in 4
• d.1 in 3

Cross Aa with Aa and the four equally likely results are AA, Aa, aA and aa; only aa has no dominant copy left to mask it, so 1 in 4 shows the recessive trait. 1 in 2 is the share that end up carriers like the parents, and 3 in 4 is the share showing the dominant trait.

In an ecosystem, bacteria and fungi that break down dead plants and animals are called

• a.producers
• b.decomposers✓
• c.scavengers
• d.herbivores

Decomposers digest dead tissue chemically and release nitrogen, phosphorus and carbon back into soil and air, closing the loop so producers can build new tissue. Scavengers tempt because they also feed on the dead, but they are animals that eat chunks and leave remains behind.

In a scientific name such as Ursus americanus, the two words give the organism's

• a.family and genus
• b.class and order
• c.order and family
• d.genus and species✓

Linnaean naming uses the two narrowest ranks, a capitalized genus followed by a lowercase species, so each organism gets one name worldwide. The ranks run kingdom, phylum, class, order, family, genus, species; family and genus tempt as the next pair up but are too broad to name one kind.