The highest-yield Science areas on the TEAS: human anatomy and physiology, the biology and chemistry of life, and scientific reasoning. Learn the core facts, study the worked example, then test yourself.
How to use this guide
Each area below gives the essential facts and rules, a worked example, and two practice questions. The answers follow each practice set, so cover them and try the questions first. A 10-question mixed set at the end blends all three areas like the real exam, with a full answer key.
Areas covered: Human Anatomy & Physiology · Biology & Chemistry · Scientific Reasoning · 16 practice questions
1. Human Anatomy & Physiology
body systems · homeostasis · anatomical terms
Key concepts
The body is organized into systems that maintain homeostasis (a stable internal environment): cardiovascular, respiratory, digestive, nervous, endocrine, urinary, skeletal, muscular, integumentary, and more.
Anatomical position is standing erect, facing forward, with palms forward. Planes: sagittal (left/right), frontal / coronal (front/back), transverse (top/bottom).
Each system has a signature job: the heart's SA node sets the beat, alveoli exchange gases, nephrons filter blood, and neurons carry signals.
Directional terms: anterior/posterior, superior/inferior, medial/lateral, proximal/distal.
Key facts & rules
Gas exchange → lungs (alveoli). Blood filtering → kidneys (nephron). Hormones → endocrine glands.
Pacemaker of the heart = the SA (sinoatrial) node.
The mid-sagittal plane divides the body into equal left and right halves.
Worked example
Which body system is chiefly responsible for gas exchange between the air and the blood?
Gas exchange means bringing oxygen in and moving carbon dioxide out.
This occurs in the lungs — part of the respiratory system.
Answer: the respiratory system.
💡 Memory hook: “Sally AVoids Bundles of Purple.” The heartbeat travels in order: SA node → AV node → Bundle of His → Purkinje fibers. (And for planes: Sagittal Splits Sides — left from right.)
Practice: Human Anatomy & Physiology
1. Which structure of the heart normally generates the electrical impulse that sets the heart rate?
A. Sinoatrial (SA) node
B. Atrioventricular (AV) node
C. Purkinje fibers
D. Bundle of His
2. The mid-sagittal plane divides the body into which of the following?
A. Front and back halves
B. Top and bottom halves
C. Inner and outer halves
D. Equal left and right halves
Answers and working
1 → A. The SA node is the heart's natural pacemaker.
2 → D. A sagittal plane runs vertically, separating left from right; mid-sagittal makes the halves equal.
2. Biology & Chemistry
cells · DNA & genetics · matter · pH
Key concepts
Cells are the basic unit of life. Prokaryotes (bacteria) lack a nucleus; eukaryotes have a nucleus and organelles. Both share a cell membrane, cytoplasm, ribosomes, and DNA.
DNA pairs A–T and G–C on antiparallel strands; ribosomes build proteins. In genetics, a dominant allele masks a recessive one.
The four states of matter are solid, liquid, gas, and plasma. An atom has protons (+), neutrons (0), and electrons (–).
The pH scale (0–14) is logarithmic: below 7 is acidic, 7 is neutral, above 7 is basic; each unit is a 10× change.
Key facts & rules
Complement of a DNA strand: swap A↔T and G↔C (DNA uses T, not U).
Atomic number = number of protons; a neutral atom has equal protons and electrons.
A pH of 3 is 10× more acidic than a pH of 4.
Worked example
If one DNA strand reads 5'-AGCT-3', what is the complementary strand?
Pair each base: A→T, G→C, C→G, T→A.
DNA uses thymine (T), not uracil (U), and the strands run antiparallel.
Answer: 3'-TCGA-5'.
💡 Memory hook: Apple Tree, Green Car. DNA base pairs are A–T (Apple–Tree) and G–C (Green–Car). Remember it’s T, not U — uracil belongs to RNA. (pH: Acids Are A-numbers, below 7.)
Practice: Biology & Chemistry
1. Which of the following structures is found in both prokaryotic and eukaryotic cells?
A. Nucleus
B. Cell membrane
C. Chloroplast
D. Golgi apparatus
2. A solution with a pH of 3 is how much more acidic than a solution with a pH of 5?
A. 100 times
B. 2 times
C. 10 times
D. 20 times
Answers and working
1 → B. A cell membrane is common to both; the nucleus and membrane-bound organelles are only in eukaryotes.
2 → A. Each pH unit is a 10× change; 3 to 5 is two units, so 10 × 10 = 100 times.
3. Scientific Reasoning
variables · controls · correlation vs causation
Key concepts
The scientific method: ask a question, form a hypothesis, experiment, analyze data, and draw a conclusion.
The independent variable is what the researcher changes; the dependent variable is what is measured. A control group gets no treatment, for comparison.
Correlation is not causation: two things moving together does not prove one causes the other.
Stronger experiments use large sample sizes, controls, and replication; reliable sources are peer-reviewed and unbiased.
Key facts & rules
Independent variable = the cause you change; dependent variable = the effect you measure.
“As X increased, Y increased” = a positive correlation.
To convert grams → kilograms, divide by 1,000 (1 kg = 1,000 g).
Worked example
Students test how fertilizer amount affects plant height, giving plants 0, 5, or 10 g and measuring height weekly. What is the independent variable?
The independent variable is what the students deliberately change.
They vary the amount of fertilizer; plant height is what they measure (the dependent variable).
Answer: the amount of fertilizer.
💡 Memory hook: DRY MIX. Dependent = Responding variable, plotted on the Y-axis; Manipulated = Independent variable, plotted on the X-axis. The thing you deliberately change goes on X.
Practice: Scientific Reasoning
1. In an experiment testing how hours of sleep affect test scores, which is the dependent variable?
A. The test score
B. The number of hours of sleep
C. The type of test
D. The time of day
2. Ice-cream sales and drowning deaths both rise in summer. What is the best conclusion?
A. Ice cream causes drowning.
B. Drowning causes ice-cream sales.
C. There is no relationship at all.
D. The two are correlated, but a third factor (hot weather) likely explains both.
Answers and working
1 → A. The test score is measured (the effect); hours of sleep is the variable that is changed.
2 → D. Correlation is not causation; a shared cause (summer heat) explains both trends.
★ Mixed practice: 10 TEAS-style questions
All three areas, like the real exam. Answer every question before checking the key below.
1. Which body system is responsible for filtering waste from the blood and producing urine? (A&P)
A. Respiratory
B. Digestive
C. Endocrine
D. Urinary
2. A neutral atom has an atomic number of 11. How many electrons does it have? (Bio/Chem)
A. 5
B. 11
C. 22
D. 0
3. In the question “Does water temperature affect how fast sugar dissolves?”, which is the independent variable? (Reasoning)
A. The amount of sugar
B. How fast the sugar dissolves
C. The temperature of the water
D. The size of the cup
4. Which of the following is the functional (filtering) unit of the kidney? (A&P)
A. Alveolus
B. Neuron
C. Villus
D. Nephron
5. In pea plants, tall (T) is dominant to short (t). What is the phenotype of a Tt plant? (Bio/Chem)
A. Short
B. Medium height
C. Tall
D. Cannot be determined
6. Which change would most improve the reliability of a study that tested a drug on only 5 people? (Reasoning)
A. Test the drug on many more people
B. Shorten the study
C. Remove the control group
D. Test only very healthy people
7. Which plane divides the body into anterior (front) and posterior (back) portions? (A&P)
A. Sagittal
B. Frontal (coronal)
C. Transverse
D. Oblique
8. Which of the following is a chemical change rather than a physical change? (Bio/Chem)
A. Ice melting
B. Cutting paper
C. Iron rusting
D. Boiling water
9. A student measures mass in grams but must report it in kilograms. What should they do to convert? (Reasoning)
A. Multiply by 1,000
B. Multiply by 100
C. Divide by 1,000
D. Divide by 10
10. Which organelle carries out protein synthesis in the cell? (Bio/Chem)
A. Mitochondrion
B. Ribosome
C. Nucleus
D. Lysosome
Answer key and explanations
# | Answer | Explanation |
|---|---|---|
1 | D · Urinary | The urinary system (kidneys) filters blood and produces urine. |
2 | B · 11 | Atomic number = number of protons; a neutral atom has an equal number of electrons. |
3 | C | Temperature is the variable deliberately changed; dissolving speed is what is measured. |
4 | D · Nephron | The nephron is the kidney's functional filtering unit. |
5 | C · Tall | A Tt plant has one dominant T, so it shows the tall phenotype. |
6 | A | A larger sample size reduces the effect of chance and improves reliability. |
7 | B | The frontal (coronal) plane separates front from back. |
8 | C | Rusting forms a new substance (iron oxide) — a chemical change; the others are physical. |
9 | C | 1 kg = 1,000 g, so divide the number of grams by 1,000. |
10 | B · Ribosome | Ribosomes assemble amino acids into proteins. |
Test yourself: free Science quiz
Take these 16 questions as a timed quiz. You get a score at the end and a written explanation for every answer. The quiz is free; you just need a free Aspire account.
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