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🔬 10 questions · answers and rationales · free

TEAS science practice questions

A free mixed TEAS science set: scientific reasoning and experiment design first, then anatomy and physiology, biology and chemistry, each with the answer and the reasoning behind it.

Tap an answer to check it, or open "Show the answer and rationale" under each question.

Question 1 of 10 · Scientific Reasoning

A student covers a burning candle with a glass jar, and the flame goes out. Which statement is an inference?

  1. The flame used up the oxygen it needed.
  2. The glass jar felt warm when it was lifted.
  3. A thin line of smoke rose inside the jar.
  4. The flame went out after about 10 seconds.
Show the answer and rationale

Answer: A

Saying the flame used up its oxygen explains why it went out, so it is an interpretation, an inference. The time, the smoke and the warm glass were all seen, timed or felt directly, so they are observations.

📚 Learn it: Logic and evidence: correlation vs causation, observation vs inference

Question 2 of 10 · Human Anatomy and Physiology

Which photoreceptors in the retina allow vision in dim light?

  1. Cones
  2. Rods
  3. Ganglion cells
  4. Ciliary cells
Show the answer and rationale

Answer: B

Rods are very sensitive to light and work in dim conditions but do not detect color. Cones need brighter light and give color vision and sharp detail. Ganglion cells carry signals into the optic nerve, and the ciliary body controls the lens rather than detecting light.

📚 Learn it: Nervous system and senses: CNS, PNS, neurons, brain regions, eye and ear

Question 3 of 10 · Biology

During digestion, starch is broken into glucose molecules by adding water across the bonds between them. What is this reaction called?

  1. Dehydration synthesis
  2. Denaturation
  3. Hydrolysis
  4. Neutralization
Show the answer and rationale

Answer: C

Hydrolysis uses water to split polymers into monomers, as when amylase breaks starch down. Dehydration synthesis removes water to build polymers (the reverse), denaturation is the loss of a protein's shape, and neutralization is an acid reacting with a base.

📚 Learn it: Macromolecules: carbohydrates, lipids, proteins and nucleic acids

Question 4 of 10 · Chemistry

A student tries to balance H₂ + O₂ → H₂O by rewriting the product as H₂O₂. Why is this not allowed?

  1. It changes the product into a different substance.
  2. It adds extra hydrogen atoms.
  3. It removes oxygen from the reaction.
  4. Subscripts in a chemical formula must always be even numbers.
Show the answer and rationale

Answer: A

Subscripts define the compound; H₂O₂ is hydrogen peroxide, not water. Equations are balanced only by changing coefficients. The change does not add hydrogen or remove oxygen, and there is no rule that subscripts must be even.

📚 Learn it: Chemical bonds and balancing equations

Question 5 of 10 · Scientific Reasoning

Data show that cities with more hospitals record more deaths each year. What is the best explanation?

  1. Deaths in a city cause more hospitals to be built there.
  2. The two numbers are linked only by random chance.
  3. Larger cities have more people and more hospitals.
  4. Hospitals cause the people in a city to die sooner.
Show the answer and rationale

Answer: C

City population is a third variable: more people means more hospitals and more deaths overall. Claiming hospitals cause deaths, or that deaths cause hospitals, confuses correlation with causation, and a pattern this consistent is not explained by chance.

📚 Learn it: Logic and evidence: correlation vs causation, observation vs inference

Question 6 of 10 · Human Anatomy and Physiology

How many pairs of cranial nerves and spinal nerves do humans have?

  1. 10 cranial pairs and 33 spinal pairs
  2. 12 cranial pairs and 31 spinal pairs
  3. 31 cranial pairs and 12 spinal pairs
  4. 12 cranial pairs and 24 spinal pairs
Show the answer and rationale

Answer: B

There are 12 pairs of cranial nerves arising from the brain and 31 pairs of spinal nerves arising from the spinal cord. The number 24 is the count of movable vertebrae, and the last choice reverses the two numbers.

📚 Learn it: Nervous system and senses: CNS, PNS, neurons, brain regions, eye and ear

Question 7 of 10 · Biology

Which macromolecule makes up most of the cell membrane's basic structure?

  1. Phospholipids
  2. Glycogen
  3. Nucleic acids
  4. Cellulose
Show the answer and rationale

Answer: A

The membrane is built on a bilayer of phospholipids, with hydrophilic heads facing water and hydrophobic tails facing inward. Glycogen stores glucose, cellulose forms plant cell walls, and nucleic acids store genetic information.

📚 Learn it: Macromolecules: carbohydrates, lipids, proteins and nucleic acids

Question 8 of 10 · Chemistry

Sodium chloride (NaCl) is held together by which type of bond?

  1. Hydrogen
  2. Nonpolar covalent
  3. Ionic
  4. Polar covalent
Show the answer and rationale

Answer: C

Sodium, a metal, transfers an electron to chlorine, a nonmetal, and the resulting Na⁺ and Cl⁻ ions attract: an ionic bond. Covalent bonds (polar or nonpolar) involve sharing between nonmetals, and hydrogen bonds are weak attractions between molecules.

📚 Learn it: Chemical bonds and balancing equations

Question 9 of 10 · Human Anatomy and Physiology

After a possible rabies exposure, a patient receives an injection of ready-made antibodies along with the first vaccine dose. Why are the antibodies given?

  1. They give immediate but temporary protection
  2. They activate the patient's own B cells to mature
  3. They create long-lasting memory cells in the patient
  4. They make the vaccine itself unnecessary
Show the answer and rationale

Answer: A

Injected antibodies are artificial passive immunity: they work at once while the vaccine has time to trigger the patient's own active, long-lasting response. Borrowed antibodies do not create memory cells, and they fade within weeks to months, so the vaccine is still needed.

📚 Learn it: Immune and lymphatic systems: innate, adaptive and vaccines

Question 10 of 10 · Human Anatomy and Physiology

What is the main function of lymph nodes?

  1. Pumping lymph back into the heart
  2. Storing bile between meals
  3. Filtering lymph and housing lymphocytes
  4. Producing red blood cells for the circulation
Show the answer and rationale

Answer: C

Lymph nodes filter lymph as it flows through them, trapping microbes and debris, and hold lymphocytes and macrophages that respond to what they catch, which is why nodes swell during infection. Red cells are made in bone marrow, bile is stored in the gallbladder, and lymph has no pump of its own.

📚 Learn it: Immune and lymphatic systems: innate, adaptive and vaccines

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