ASVAB General Science: Core Formulas to Remember

Physics Fundamentals for the ASVAB General Science Test

Physics is the branch of science concerned with the nature and properties of matter and energy. It includes mechanics, heat, light, sound, electricity, magnetism, and atomic structure. For the ASVAB General Science Test, you must understand basic physics principles and apply them in simple problem-solving scenarios. This section focuses on the essential concepts, equations, and applications commonly tested.

Understanding Motion and Forces

Distance, Displacement, Speed, and Velocity

Motion is the change in position of an object over time. There are a few basic terms used to describe motion:

• Distance refers to how much ground an object has covered during its motion. It is a scalar quantity, meaning it has magnitude only.
• Displacement is the change in position of an object and includes direction, making it a vector quantity.
• Speed is how fast an object is moving, regardless of direction. The formula for speed is:
  Speed=DistanceTimeors=dt\text{Speed} = \frac{\text{Distance}}{\text{Time}} \quad \text{or} \quad s = \frac{d}{t}
• Velocity is the speed of an object in a particular direction. The formula is:
  Velocity=DisplacementTimeorv=Δdt\text{Velocity} = \frac{\text{Displacement}}{\text{Time}} \quad \text{or} \quad v = \frac{\Delta d}{t}
• Acceleration is the rate of change of velocity. This can occur through a change in speed or direction. The formula is:
  a=Δvta = \frac{\Delta v}{t}

Where Δv\Delta v represents the change in velocity and tt is the time taken.

These concepts are the basis for understanding more complex systems and questions involving moving objects.

Newton’s Three Laws of Motion

Sir Isaac Newton proposed three fundamental laws of motion that describe the behavior of objects.

1. First Law (Law of Inertia):
   An object at rest remains at rest, and an object in motion continues in motion at a constant velocity unless acted upon by a net external force. This law explains why seat belts are important—without them, your body would continue moving forward in a car crash.
2. Second Law (Force = Mass × Acceleration):
   Newton’s second law shows how the velocity of an object changes when it is subjected to an external force. The formula is:
   F=maF = ma
   Where FF is the force applied, mm is the mass of the object, and aa is the acceleration.
3. Third Law (Action and Reaction):
   For every action, there is an equal and opposite reaction. This explains phenomena like how rockets launch by pushing exhaust gases downward to lift themselves upward.

These laws are widely used in practical scenarios, and questions on the ASVAB may ask you to identify which law applies to a given situation.

Energy, Work, and Power

Work

Work is done when a force is applied to an object, and the object moves in the direction of the applied force. Work is measured in joules (J). The formula is:

W=FdW = Fd

Where WW is the work done, FF is the force applied, and dd is the distance over which the force is applied.

If there is no movement, no work is done, even if a force is applied.

Energy

Energy is the ability to do work. There are many types of energy, but in mechanics, the two most important are:

• Kinetic Energy: The energy an object possesses due to its motion. The formula is:
  KE=12mv2KE = \frac{1}{2}mv^2
  Where mm is mass and vv is velocity.
• Potential Energy: The energy stored in an object because of its position. For example, a rock held above the ground has gravitational potential energy. The formula is:
  PE=mghPE = mgh
  Where mm is mass, gg is gravitational acceleration (about 9.8 m/s²), and hh is the height above the ground.

The total mechanical energy of a system is the sum of kinetic and potential energy.

Power

Power is the rate at which work is done or energy is transferred. It is measured in watts (W). The formula is:

P=WtP = \frac{W}{t}

Where PP is power, WW is work, and tt is time. For example, lifting a heavy object quickly requires more power than lifting it slowly, even if the same amount of work is done.

Simple Machines and Mechanical Advantage

Simple machines make work easier by changing the direction or magnitude of a force. Common types include:

• Lever
• Pulley
• Wheel and axle
• Inclined plane
• Wedge
• Screw

These machines provide a mechanical advantage, which allows a smaller force to move a larger load. Mechanical advantage (MA) is the ratio of output force to input force:

MA=FoutFinMA = \frac{F_{\text{out}}}{F_{\text{in}}}

Understanding simple machines and their efficiency can help you solve mechanical reasoning questions on the ASVAB.

Waves, Sound, and Light

Wave Properties

A wave is a disturbance that transfers energy from one place to another without transferring matter. There are two types of waves:

• Mechanical Waves (e.g., sound): Require a medium to travel through.
• Electromagnetic Waves (e.g., light): Do not need a medium and can travel through a vacuum.

Important wave properties include:

• Wavelength (λ): Distance between two successive crests or troughs.
• Frequency (f): Number of waves that pass a point per second.
• Amplitude: Maximum displacement of the wave.
• Speed (v): How fast the wave travels. The formula is:
  v=fλv = f\lambda

Sound Waves

Sound is a mechanical longitudinal wave. It requires a medium such as air, water, or a solid to travel. The speed of sound varies with the medium:

• Fastest in solids
• Slower in liquids
• Slowest in gases

High frequency means high pitch; low frequency means low pitch.

Light Waves

Light is an electromagnetic wave that travels fastest in a vacuum. It behaves both as a wave and a particle (called a photon). Key behaviors include:

• Reflection: Bouncing off a surface.
• Refraction: Bending when passing through different materials.
• Diffraction: Spreading around obstacles.
• Absorption: When a material captures the light energy.

Understanding how light and sound work is essential for answering questions related to vision, hearing, and energy transfer.

Electricity and Magnetism

Electric Charge and Static Electricity

Matter is made of atoms that contain charged particles: electrons (negative) and protons (positive). When objects gain or lose electrons, they become charged:

• Like charges repel.
• Opposite charges attract.

Static electricity results from the accumulation of charge on an object.

Current, Voltage, and Resistance

• Current (I): The flow of electric charge, measured in amperes (A).
• Voltage (V): The electrical potential difference that pushes the charge, measured in volts (V).
• Resistance (R): The opposition to current flow, measured in ohms (Ω).

These quantities are related by Ohm’s Law:

V=IRV = IR

This equation is used to calculate current, voltage, or resistance in electrical circuits. For example, if a circuit has 10 volts and 2 ohms of resistance, the current is:

I=VR=102=5 AI = \frac{V}{R} = \frac{10}{2} = 5\,A

Circuits and Magnetism

Electricity flows in a closed loop called a circuit. There are two main types:

• Series Circuit: One path for current to flow.
• Parallel Circuit: Multiple paths for current.

Magnetism arises from the motion of electric charges. A current-carrying wire generates a magnetic field. Electromagnets use this principle to create controllable magnetic fields.

Magnets have poles: north and south. Opposite poles attract; like poles repel.

Understanding the basics of circuits and magnetism is helpful for questions involving household electronics or simple machinery.

Chemistry Concepts for the ASVAB General Science Test

Chemistry is the science of matter and the changes it undergoes. For the ASVAB General Science Test, chemistry questions assess your understanding of basic concepts related to atoms, elements, compounds, reactions, states of matter, and the properties of substances. This section presents a detailed review of the foundational topics in chemistry that are commonly covered in the test.

Atomic Structure and the Periodic Table

Structure of an Atom

All matter is composed of atoms, which are the smallest units that retain the properties of an element. An atom consists of three primary subatomic particles:

• Protons: positively charged particles located in the nucleus
• Neutrons: neutral particles also located in the nucleus
• Electrons: negatively charged particles that orbit the nucleus in electron shells

The number of protons in an atom determines its atomic number and defines the element. For example, any atom with one proton is hydrogen, while any atom with six protons is carbon.

The mass of an atom is concentrated in the nucleus, as protons and neutrons are much heavier than electrons. The atomic mass is the sum of protons and neutrons.

Isotopes

Isotopes are atoms of the same element that have the same number of protons but different numbers of neutrons. For example, carbon-12 and carbon-14 are both isotopes of carbon, but carbon-14 has two additional neutrons. Isotopes of some elements are unstable and undergo radioactive decay, releasing energy in the process.

The Periodic Table

The periodic table is a chart that organizes elements by increasing atomic number and groups them based on similar chemical properties.

• Periods are horizontal rows, representing increasing energy levels.
• Groups or families are vertical columns, and elements in the same group have similar properties.

Key groups include:

• Group 1: Alkali metals – highly reactive with water
• Group 2: Alkaline earth metals – reactive, but less so than alkali metals
• Group 17: Halogens – very reactive nonmetals
• Group 18: Noble gases – inert and non-reactive

The periodic table helps predict an element’s reactivity, state of matter, and bonding behavior.

Chemical Bonds and Reactions

Types of Chemical Bonds

Atoms form chemical bonds to achieve stable electron configurations, typically aiming for a full outer shell of electrons.

• Ionic bonds form between metals and nonmetals. One atom donates electrons, and the other gains them. This creates charged particles called ions. The opposite charges attract, forming a bond.
• Covalent bonds form between nonmetals that share electrons. These bonds are common in organic molecules and gases like oxygen and nitrogen.
• Metallic bonds occur between metal atoms, where electrons are shared in a “sea” of electrons, contributing to properties like conductivity and malleability.

Understanding how atoms bond helps you interpret formulas and predict compound behavior.

Chemical Reactions

A chemical reaction involves the transformation of reactants into products. Atoms are rearranged, but the number of each type of atom remains the same.

Signs of a chemical reaction include:

• Formation of a gas (bubbles)
• Formation of a precipitate (solid from liquid)
• Color change
• Temperature change
• Emission of light or sound

Chemical reactions follow the law of conservation of mass: mass is neither created nor destroyed. This means the total mass of reactants equals the total mass of products.

Balancing Equations

Balancing a chemical equation ensures that the same number of atoms of each element are present on both sides of the reaction.

Example:

H2+O2→H2O\text{H}_2 + \text{O}_2 \rightarrow \text{H}_2\text{O}

This equation is not balanced because there are two oxygen atoms on the left but only one on the right. The balanced equation is:

2H2+O2→2H2O2\text{H}_2 + \text{O}_2 \rightarrow 2\text{H}_2\text{O}

Balancing equations is an essential skill for interpreting reactions accurately.

States of Matter and Changes

Four States of Matter

Matter exists in four physical states, each with distinct properties:

• Solids: fixed shape and volume, tightly packed particles
• Liquids: fixed volume, but take the shape of their container; particles can slide past each other.
• Gases: no fixed shape or volume; particles move freely and rapidly
• Plasma: high-energy state found in stars; composed of ions and free electrons

These states can change through the addition or removal of energy.

Phase Changes

Physical changes between states of matter include:

• Melting: solid to liquid
• Freezing: liquid to solid
• Vaporization: liquid to gas (includes boiling and evaporation)
• Condensation: gas to liquid
• Sublimation: solid to gas (dry ice)
• Deposition: gas to solid (frost)

These changes involve energy transfer but do not alter the chemical composition of the substance.

Temperature and Heat

• Temperature measures the average kinetic energy of particles.
• Heat is the energy transferred due to a temperature difference.

Substances absorb or release heat during phase changes without changing temperature until the change is complete.

Acids, Bases, and the pH Scale

Acids

Acids are substances that release hydrogen ions (H⁺) when dissolved in water. Characteristics include:

• Sour taste
• Corrosive to metals
• pH less than 7
• Turns blue litmus paper red

Common examples include hydrochloric acid (HCl), sulfuric acid (H₂SO₄), and citric acid.

Bases

Bases release hydroxide ions (OH⁻) in water. Characteristics include:

• Bitter taste
• Slippery feel
• pH greater than 7
• Turns red litmus paper blue

Common examples include sodium hydroxide (NaOH) and ammonia (NH₃).

pH Scale

The pH scale ranges from 0 to 14 and measures the concentration of hydrogen ions:

• 0–6.9: Acidic
• 7: Neutral (pure water)
• 7.1–14: Basic

The scale is logarithmic, so each whole number represents a tenfold change in acidity or basicity. A solution with a pH of 4 is ten times more acidic than one with a pH of 5.

Neutralization

When an acid and a base react, they neutralize each other to form water and a salt:

HCl+NaOH→NaCl+H2O\text{HCl} + \text{NaOH} \rightarrow \text{NaCl} + \text{H}_2\text{O}

This reaction is important in digestion, industrial processes, and environmental science.

Chemical Formulas and Stoichiometry

Understanding Chemical Formulas

Chemical formulas indicate the elements in a compound and the number of atoms of each.

• H₂O: 2 hydrogen atoms, 1 oxygen atom (water)
• CO₂: 1 carbon atom, 2 oxygen atoms (carbon dioxide)
• NaCl: 1 sodium, 1 chlorine (table salt)

Formulas help identify the type and quantity of atoms in a molecule.

Molecular and Empirical Formulas

• A molecular formula shows the exact number of atoms in a molecule. Example: C₆H₁₂O₆ (glucose)
• An empirical formula shows the simplest whole-number ratio of atoms. Example: CH₂O (simplified version of glucose)

The empirical formula is useful in analyzing unknown compounds and determining molecular structures.

Stoichiometry

Stoichiometry involves using balanced chemical equations to calculate:

• Amount of reactants needed
• Amount of products formed
• Mass relationships in a reaction

For example, in the reaction:

2H2+O2→2H2O2\text{H}_2 + \text{O}_2 \rightarrow 2\text{H}_2\text{O}

Two moles of hydrogen react with one mole of oxygen to produce two moles of water. This ratio helps you determine quantities needed or produced in a reaction.

Understanding stoichiometry is crucial for interpreting chemical reactions quantitatively.

Solutions and Mixtures

Mixtures vs. Compounds

• Mixtures are physical combinations of substances that retain their individual properties. They can be separated by physical means.
• Compounds are chemical combinations of elements in fixed proportions and require chemical reactions to separate.

Mixtures can be:

• Homogeneous: Uniform throughout (e.g., salt water)
• Heterogeneous: Not uniform; visible components (e.g., salad)

Solutions

A solution is a type of homogeneous mixture where one substance is dissolved in another.

• Solute: the substance being dissolved (e.g., salt)
• Solvent: the substance doing the dissolving (e.g., water)

Water is known as the universal solvent because it can dissolve many substances.

The concentration of a solution refers to how much solute is dissolved in a given amount of solvent.

Earth and Space Science Concepts for the ASVAB General Science Test

Earth and space science examines the physical characteristics of our planet and the celestial bodies around it. The ASVAB General Science Test includes questions from geology, meteorology, astronomy, oceanography, and environmental science. A basic understanding of Earth’s structure, weather systems, and solar system dynamics is essential to perform well in this section.

Structure of the Earth

Layers of the Earth

The Earth is composed of several distinct layers, each with unique characteristics:

• Crust: The outermost layer, where we live. It consists of solid rock and is divided into continental and oceanic crust. The crust is relatively thin compared to other layers.
• Mantle: Located beneath the crust, the mantle extends to a depth of about 2,900 kilometers. It consists of semi-solid rock that moves slowly due to convection currents.
• Outer Core: A layer of molten iron and nickel that surrounds the inner core. This liquid metal creates Earth’s magnetic field.
• Inner Core: A dense, solid sphere composed mainly of iron and nickel. Despite high temperatures, the immense pressure keeps it solid.

These layers play a crucial role in geological activity, such as earthquakes and volcanic eruptions.

Plate Tectonics

The Earth’s crust is broken into large pieces called tectonic plates. These plates float on the semi-fluid asthenosphere and are in constant motion. The interactions between these plates cause many geological events.

• Divergent boundaries: Plates move apart, forming new crust (e.g., mid-ocean ridges).
• Convergent boundaries: Plates move toward each other, leading to mountain formation or subduction (e.g., Himalayas).
• Transform boundaries: Plates slide past each other, causing earthquakes (e.g., San Andreas Fault).

Plate tectonics helps explain the distribution of earthquakes, volcanoes, and mountain ranges.

Rock Cycle and Earth’s Surface

Types of Rocks

Rocks are classified into three main types based on their formation process:

• Igneous rocks: Formed from cooled molten rock (magma or lava). Examples include granite and basalt.
• Sedimentary rocks: Created from the accumulation of sediments compressed over time. Examples include sandstone and limestone.
• Metamorphic rocks: Formed when existing rocks are altered by heat, pressure, or chemical processes. Examples include marble and slate.

Understanding these types helps in identifying geological processes and rock origins.

The Rock Cycle

The rock cycle is a continuous process where rocks change from one type to another. For example:

• Magma cools to form igneous rock.
• Weathering and erosion break rocks into sediments.
• Sediments compact into sedimentary rock.
• Heat and pressure transform rocks into metamorphic rock.
• Metamorphic rock may melt into magma, completing the cycle.

This process highlights the dynamic nature of Earth’s surface.

Weathering and Erosion

• Weathering is the breakdown of rocks by physical (mechanical), chemical, or biological processes.
• Erosion is the movement of weathered material by wind, water, ice, or gravity.

Together, weathering and erosion shape landscapes, create soil, and transport sediments.

Atmosphere and Weather

Composition of the Atmosphere

The Earth’s atmosphere is a mixture of gases surrounding the planet, critical for sustaining life and regulating temperature. It consists of:

• 78% nitrogen
• 21% oxygen
• 1% other gases (including carbon dioxide, argon, and water vapor)

Atmospheric Layers

The atmosphere is divided into five main layers based on temperature changes:

• Troposphere: The Lowest layer, where weather occurs.
• Stratosphere: Contains the ozone layer, which absorbs ultraviolet radiation.
• Mesosphere: Protects Earth by burning up meteors.
• Thermosphere: High-energy radiation causes temperatures to rise.
• Exosphere: Outermost layer, gradually fading into space.

Understanding these layers is important for questions on weather, radiation, and atmospheric phenomena.

Weather vs. Climate

• Weather refers to short-term atmospheric conditions, such as temperature, humidity, wind, and precipitation.
• Climate describes the long-term average weather patterns of a region.

While the weather can change daily, the climate remains stable over decades or centuries.

Weather Patterns and Systems

The weather is influenced by factors such as air pressure, humidity, wind, and temperature.

• High-pressure systems are associated with clear, calm weather.
• Low-pressure systems often bring clouds and precipitation.

Common weather systems include:

• Fronts: Boundaries between air masses.
  • Cold fronts bring cooler air and storms.
  • Warm fronts bring gradual warming and rain.
• Thunderstorms are caused by unstable, moist air rising rapidly.
• Hurricanes: Large tropical storms with high winds and heavy rainfall.
• Tornadoes: Spinning columns of air formed during severe thunderstorms.

Understanding weather systems helps interpret real-life weather events and atmospheric behavior.

Water Systems and Oceans

The Water Cycle

The water cycle is the continuous movement of water on, above, and below the surface of the Earth. It involves:

• Evaporation: Water turns into vapor from oceans and lakes.
• Condensation: Vapor cools and forms clouds.
• Precipitation: Water falls as rain, snow, or hail.
• Runoff: Water flows over land and returns to bodies of water.
• Infiltration: Water soaks into the ground, replenishing aquifers.

This cycle maintains Earth’s water balance and supports ecosystems.

Ocean Currents and Tides

• Ocean currents are large-scale movements of water influenced by wind, Earth’s rotation (Coriolis effect), and salinity.
• Tides are the periodic rise and fall of sea levels caused by gravitational forces from the Moon and Sun.

Understanding oceans is vital because they regulate climate and weather, support marine life, and affect human activities.

Earth’s Natural Resources and Environmental Science

Renewable and Nonrenewable Resources

• Renewable resources can be replenished naturally in a short time. Examples: solar energy, wind, water, and biomass.
• Nonrenewable resources exist in limited quantities. Examples: fossil fuels (coal, oil, natural gas), and minerals.

Managing these resources responsibly is essential for sustainability and environmental protection.

Human Impact on the Environment

Human activity can significantly affect the environment:

• Deforestation reduces biodiversity and increases carbon dioxide levels.
• Pollution affects air, water, and soil quality.
• Climate change is driven by the greenhouse effect, where gases trap heat and raise global temperatures.

Preserving the environment requires reducing emissions, recycling, and using cleaner energy sources.

The Solar System

The Sun and Its Importance

The Sun is a medium-sized star at the center of the solar system. It provides energy through nuclear fusion, converting hydrogen into helium. This energy drives weather, supports plant life, and warms the planet.

The Sun’s gravitational pull keeps planets and other objects in orbit.

The Planets

There are eight major planets in the solar system:

• Inner (terrestrial) planets: Mercury, Venus, Earth, Mars
  • Rocky surfaces, smaller, closer to the Sun
• Outer (gas) giants: Jupiter, Saturn, Uranus, Neptune
  • Made mostly of gases, larger, with ring systems, and many moons

Each planet has unique characteristics, such as atmospheres, weather, and magnetic fields.

Dwarf Planets and Moons

• Dwarf planets like Pluto are smaller and do not clear their orbital path.
• Moons are natural satellites that orbit planets. Earth’s Moon influences tides and stabilizes Earth’s rotation.

Understanding planetary classification helps distinguish celestial bodies in the solar system.

Asteroids, Comets, and Meteoroids

• Asteroids are rocky objects, mainly found in the asteroid belt between Mars and Jupiter.
• Comets are made of ice and dust; they form tails when approaching the Sun.
• Meteoroids are small rock or metal fragments in space.
  • Meteor: A meteoroid that burns in the atmosphere (shooting star).
  • Meteorite: A meteor that lands on Earth.

These objects help scientists understand the formation of the solar system.

The Universe and Beyond

Stars and Galaxies

• Stars are massive spheres of plasma that emit light and heat through fusion.
  • Lifecycle stages include nebula, main sequence, red giant, supernova, and black hole.
• Galaxies are collections of stars, gas, and dust bound by gravity. Our galaxy, the Milky Way, contains billions of stars.

Telescopes help study distant galaxies, stars, and cosmic phenomena.

Big Bang Theory

The Big Bang Theory is the leading explanation of how the universe began. It proposes that the universe started from a singularity around 13.8 billion years ago and has been expanding ever since.

Evidence includes cosmic background radiation and redshift in light from distant galaxies.

Understanding the origins and structure of the universe is important for basic astronomy questions on the test.

Biological Science Concepts for the ASVAB General Science Test

Biology is the study of living organisms, including their structure, function, growth, evolution, distribution, and relationships. For the ASVAB General Science Test, you are expected to understand basic biological concepts such as cell structure, genetics, human anatomy, ecosystems, and classification. This section provides a detailed overview of these topics to help you prepare.

The Cell: Structure and Function

Types of Cells

All living organisms are made up of cells. Cells are the basic structural and functional units of life. There are two main types:

• Prokaryotic cells: Found in bacteria and archaea. These cells do not have a nucleus or membrane-bound organelles. Their DNA is located in the cytoplasm.
• Eukaryotic cells: Found in plants, animals, fungi, and protists. These cells have a defined nucleus and various organelles enclosed by membranes.

Understanding the difference between these cell types helps you answer questions about microorganisms and cell biology.

Cell Organelles

Key structures within eukaryotic cells include:

• Nucleus: Contains genetic material (DNA) and controls cell activities.
• Mitochondria: The powerhouse of the cell; produces energy through cellular respiration.
• Ribosomes: Synthesize proteins.
• Endoplasmic Reticulum (ER): Processes and transports proteins (rough ER) and lipids (smooth ER).
• Golgi Apparatus: Modifies, packages, and distributes molecules.
• Lysosomes: Contain digestive enzymes to break down waste.
• Cell Membrane: Controls what enters and exits the cell.
• Cell Wall: Provides structure in plant cells.
• Chloroplasts: Found in plant cells; perform photosynthesis.

Recognizing the function of these organelles is essential for understanding how cells operate and interact with their environment.

Cell Processes

Cells carry out several important processes:

• Photosynthesis occurs in the chloroplasts of plant cells. Converts sunlight, carbon dioxide, and water into glucose and oxygen.
  6CO2+6H2O+sunlight→C6H12O6+6O26CO_2 + 6H_2O + \text{sunlight} \rightarrow C_6H_{12}O_6 + 6O_2
• Cellular respiration occurs in mitochondria. Breaks down glucose to produce energy (ATP).
  C6H12O6+6O2→6CO2+6H2O+ATPC_6H_{12}O_6 + 6O_2 \rightarrow 6CO_2 + 6H_2O + \text{ATP}
• Mitosis: A type of cell division resulting in two identical daughter cells, used for growth and repair.
• Meiosis: Cell division that produces gametes (sperm and eggs) with half the normal number of chromosomes.

These processes are key to understanding life functions and reproduction.

Genetics and Heredity

DNA and Chromosomes

• DNA (deoxyribonucleic acid) is the molecule that stores genetic information. It is shaped like a double helix and made of four bases: adenine, thymine, cytosine, and guanine.
• Genes are segments of DNA that code for specific traits.
• Chromosomes are structures in the nucleus made of DNA. Humans have 23 pairs of chromosomes, for a total of 46.

Genetic information is passed from parents to offspring through reproduction.

Mendelian Genetics

Gregor Mendel discovered the basic principles of heredity by studying pea plants. His laws include:

• Law of Segregation: Each parent passes one allele for a trait to the offspring.
• Law of Independent Assortment: Traits are passed independently of one another.

Traits can be:

• Dominant: Expressed even if only one allele is present (e.g., brown eyes).
• Recessive: Only expressed when two copies are present (e.g., blue eyes).

Understanding inheritance helps explain family traits and genetic disorders.

Mutations and Genetic Variation

• Mutation: A change in DNA that can lead to variations in traits. Some mutations are beneficial, some are harmful, and some are neutral.
• Genetic variation is important for natural selection and evolution, as it allows populations to adapt to changing environments.

These concepts are essential for understanding evolution and the diversity of life.

Human Body Systems

Overview of Human Organ Systems

The human body is organized into systems, each with specific functions. Key systems include:

• Circulatory system: Transports oxygen, nutrients, and waste. Includes the heart, blood, and blood vessels.
• Respiratory system: Facilitates gas exchange. Includes lungs, trachea, and diaphragm.
• Digestive system: Breaks down food. Includes the mouth, esophagus, stomach, intestines, liver, and pancreas.
• Nervous system: Controls body activities using electrical signals. Includes the brain, spinal cord, and nerves.
• Muscular system: Allows movement. Works with the skeletal system.
• Skeletal system: Provides structure, support, and protection. Stores minerals and makes blood cells.
• Excretory system: Removes waste. Includes kidneys, ureters, bladder, and urethra.
• Immune system: Defends against infection. Includes white blood cells, lymph nodes, and antibodies.
• Endocrine system: Regulates body functions through hormones. Includes glands such as the thyroid and adrenal glands.

Understanding these systems is vital for questions related to human health and physiology.

The Five Senses

The body gathers information through five main senses:

• Sight (eyes)
• Hearing (ears)
• Taste (tongue)
• Smell (nose)
• Touch (skin)

These senses are connected to the nervous system and help organisms respond to their environment.

Classification of Life

Levels of Biological Organization

Organisms are structured hierarchically:

• Cell: Basic unit of life
• Tissue: A Group of similar cells
• Organ: A Group of tissues working together
• Organ system: A Group of organs with a shared function
• Organism: An individual living being

This organization is consistent across all complex life forms.

Taxonomy and Classification

Biologists use a classification system to organize living things. The system uses the following hierarchy:

• Domain
• Kingdom
• Phylum
• Class
• Order
• Family
• Genus
• Species

A common mnemonic to remember the order is: “Dear King Philip Came Over For Great Spaghetti.”

For example, humans are classified as:

• Kingdom: Animalia
• Phylum: Chordata
• Class: Mammalia
• Order: Primates
• Family: Hominidae
• Genus: Homo
• Species: sapiens

Binomial nomenclature uses the genus and species to give each organism a scientific name, such as Homo sapiens.

Ecology and Ecosystems

Components of an Ecosystem

An ecosystem includes all living (biotic) and non-living (abiotic) components in a specific area. Components include:

• Producers: Organisms like plants that make their food through photosynthesis.
• Consumers: Organisms that eat other organisms. This includes herbivores, carnivores, and omnivores.
• Decomposers: Break down dead organisms and recycle nutrients (e.g., fungi and bacteria).

Understanding food chains and webs is essential for ecological questions.

Energy Flow

Energy flows through ecosystems in the following way:

• Sun → Producers → Primary Consumers → Secondary Consumers → Tertiary Consumers → Decomposers

Only about 10% of energy is passed from one level to the next, with most energy lost as heat.

Population and Environmental Relationships

• Population: A Group of the same species in a given area.
• Community: All the populations in a specific area.
• Habitat: The environment where an organism lives.
• Niche: The role an organism plays in its environment.

Relationships between organisms include:

• Predation: One organism hunts another.
• Competition: Organisms fight for resources.
• Symbiosis: A close relationship between species.
  • Mutualism: Both benefit
  • Commensalism: One benefits, the other is unaffected
  • Parasitism: One benefits, the other is harmed

These concepts help explain how ecosystems function and maintain balance.

Evolution and Natural Selection

Evolution

Evolution is the process by which species change over time due to genetic variation and environmental pressures.

• Fossils and comparative anatomy provide evidence of evolution.
• Organisms that are better adapted to their environment are more likely to survive and reproduce.

Natural Selection

Proposed by Charles Darwin, natural selection is the process by which traits that enhance survival become more common in a population.

Key principles:

• Variation exists within populations.
• More offspring are produced than can survive.
• Individuals with advantageous traits survive and pass them on.
• Over time, these traits become more common.

This concept explains the diversity and adaptability of life on Earth.

Final Thoughts

The ASVAB General Science Test serves as a broad assessment of your understanding across key scientific disciplines—physics, chemistry, earth and space science, and biology. While the questions are not overly complex, they require a solid grasp of basic principles and the ability to apply them in practical situations. Success on this portion of the exam depends more on comprehension and logical thinking than rote memorization. By focusing on core topics like motion and force, atomic structure, weather patterns, and human biology, you can build the confidence needed to tackle any question. Regular review, practice without a calculator, and familiarity with diagrams and scientific terms will strengthen your readiness. Ultimately, this test section not only gauges your science knowledge but also reflects your problem-solving skills and preparedness for technical roles in the military. With consistent study and a clear strategy, you can approach the General Science Test with confidence and achieve a strong score.