TEAS Science practice test

Free TEAS Science questions with explanations: anatomy and physiology, biology, chemistry and scientific reasoning, weighted like the real section.

questions: 50
scored: 44
72 s per question: 60 min
after the break: 3 of 4

What's on TEAS Science

The Science section has 50 questions (44 scored) and 60 minutes. It's section 3 of 4 on the ATI TEAS 7.

Free Science questions

15 questions

Human Anatomy and Physiology · 1 of 15A woman has regular 28-day menstrual cycles (day 1 is the first day of menstrual bleeding). Her serum progesterone measured on day 21 is very low. Which is the most likely explanation?

She did not ovulate this cycle, so no corpus luteum formed to secrete progesterone.
She ovulated on day 14, and the corpus luteum had already degenerated by day 21.
She is in the early follicular phase, when progesterone is not yet expected.
She is pregnant, because hCG shuts down the corpus luteum.

TEAS Science practice test with answers

Every question above with its answer and the reasoning. Open one to check yourself, or read straight through.

Science · Human Anatomy and PhysiologyA woman has regular 28-day menstrual cycles (day 1 is the first day of menstrual bleeding). Her serum progesterone measured on day 21 is very low. Which is the most likely explanation?
- A. She did not ovulate this cycle, so no corpus luteum formed to secrete progesterone. (correct)
- B. She ovulated on day 14, and the corpus luteum had already degenerated by day 21.
- C. She is in the early follicular phase, when progesterone is not yet expected.
- D. She is pregnant, because hCG shuts down the corpus luteum.
In a 28-day cycle, day 21 falls in the mid-luteal phase, when the corpus luteum normally makes peak progesterone. A low value suggests no ovulation occurred. The corpus luteum degenerates near day 26 to 28 (not by day 21), and hCG maintains the corpus luteum in pregnancy rather than shutting it down.
Science · BiologyA tRNA molecule has the anticodon 5'-GCA-3'. Which mRNA codon does this tRNA recognize?
- A. 5'-UGC-3' (correct)
- B. 5'-CGU-3'
- C. 5'-GCA-3'
- D. 5'-ACG-3'
Codon and anticodon pair antiparallel, so the codon pairing with 5'-GCA-3' is 3'-CGU-5', which is written 5'-UGC-3'. 5'-CGU-3' is tempting because it is the base-by-base complement, but it is read in the wrong direction.
Science · ChemistryAmmonia reacts with oxygen according to the unbalanced equation NH3 + O2 → NO + H2O. After the equation is balanced with the smallest whole-number coefficients, how many moles of H2O form when 10 mol of O2 react completely?
- A. 10 mol
- B. 12 mol (correct)
- C. 15 mol
- D. 6 mol
The balanced equation is 4 NH3 + 5 O2 → 4 NO + 6 H2O, so 5 mol O2 give 6 mol H2O and 10 mol O2 give 12 mol. The value 15 mol comes from wrongly using the NO coefficient of 4 (10 × 6/4).
Science · Scientific ReasoningA researcher tests whether the genre of background music (classical, pop, or none) affects typing accuracy. Sixty volunteers are randomly assigned to three groups. Which of the following should be kept the same for all three groups? Select all that apply.
- A. The passage that volunteers type (correct)
- B. The genre of music played
- C. The length of the typing test (correct)
- D. The percentage of words typed correctly
- E. The keyboard model used (correct)
Controlled variables such as the passage, test length, and keyboard must be identical so that only music differs between groups. Music genre is the independent variable and typing accuracy is the dependent variable, so neither is held constant.
Science · Human Anatomy and PhysiologyA patient has normal muscle strength and speaks and understands clearly. When asked to touch her nose, her finger overshoots and trembles, and she walks with her feet wide apart and sways. Which brain structure is most likely damaged?
- A. Basal ganglia
- B. Medulla oblongata
- C. Hypothalamus
- D. Cerebellum (correct)
The cerebellum coordinates voluntary movement and balance, and damage causes overshooting, intention tremor and a wide-based unsteady gait. Basal ganglia damage tends to cause tremor at rest and difficulty starting movement, not overshooting during a targeted movement.
Science · BiologyWhich of the following structures are found in both typical plant cells and typical animal cells? Select all that apply.
- A. Mitochondria (correct)
- B. Cell wall made of cellulose
- C. Ribosomes (correct)
- D. Chloroplasts
- E. Golgi apparatus (correct)
- F. Large central vacuole
Both cell types are eukaryotic and contain mitochondria, ribosomes and a Golgi apparatus. The cellulose cell wall, chloroplasts and large central vacuole are characteristic of plant cells, not animal cells.
Science · ChemistryCarbon-12 and carbon-14 atoms are both atoms of carbon. In which of the following do they differ?
- A. Number of protons
- B. Number of neutrons (correct)
- C. Nuclear charge
- D. Atomic number
Isotopes of one element have the same number of protons (the same atomic number and nuclear charge) but different numbers of neutrons, so their mass numbers differ. Proton number is what defines the element, so it cannot differ.
Science · Scientific ReasoningA student wants to know whether water temperature affects how fast an antacid tablet dissolves. She drops a whole tablet into 100 mL of water at 10 °C, half a tablet into 100 mL of water at 30 °C, and a crushed tablet into 100 mL of water at 50 °C, then times each trial. What is the main flaw in this design?
- A. She tested only three temperatures
- B. The form and amount of tablet differ along with temperature, so a difference in dissolving time cannot be attributed to temperature alone (correct)
- C. She used the same volume of water in every trial
- D. She measured time instead of counting bubbles
Tablet form and amount change together with temperature, which makes them confounding variables. Using the same water volume in every trial is good control, not a flaw, and three temperatures are enough to show a trend.
Science · Human Anatomy and PhysiologyA medication blocks the effects of the parasympathetic nervous system on its target organs. Which pair of effects is most likely?
- A. Faster heart rate and dry mouth (correct)
- B. Slower heart rate and increased salivation
- C. Constricted pupils and increased intestinal motility
- D. Bronchoconstriction and increased gastric secretion
The parasympathetic system slows the heart and promotes salivation, so blocking it lets heart rate rise and reduces saliva. The other options list effects that parasympathetic activity itself produces, which would be reduced rather than caused by the blocker.
Science · Human Anatomy and PhysiologyWhich of the following are functions of the liver? Select all that apply.
- A. Producing bile (correct)
- B. Storing bile until a meal is eaten
- C. Synthesizing most plasma proteins, including albumin (correct)
- D. Converting ammonia to urea (correct)
- E. Secreting pancreatic lipase
- F. Producing insulin
The liver makes bile, synthesizes albumin and other plasma proteins, and converts toxic ammonia to urea. The gallbladder, not the liver, stores bile, and the pancreas makes lipase and insulin.
Science · Human Anatomy and PhysiologyWhich combination of conditions in the capillaries of a sprinting athlete's thigh muscle most favors the release of oxygen from hemoglobin?
- A. Low carbon dioxide, high pH, high temperature
- B. High carbon dioxide, low pH, high temperature (correct)
- C. High carbon dioxide, low pH, low temperature
- D. Low carbon dioxide, low pH, high temperature
Active muscle produces CO2, acid, and heat; all three lower hemoglobin's affinity for oxygen and shift the dissociation curve to the right. Choice C is tempting because high CO2 and low pH are correct, but low temperature would increase hemoglobin's hold on oxygen.
Science · Human Anatomy and PhysiologyA tumor of the parathyroid gland secretes large amounts of parathyroid hormone (PTH). Which combination of serum findings is expected?
- A. High calcium and high phosphate
- B. Low calcium and high phosphate
- C. High calcium and low phosphate (correct)
- D. Low calcium and low phosphate
PTH raises serum calcium by stimulating bone resorption, increasing renal calcium reabsorption, and promoting vitamin D activation. It also decreases renal reabsorption of phosphate, so phosphate is lost in urine and serum phosphate falls, even though bone breakdown releases some phosphate.
Science · Human Anatomy and PhysiologyA toxin blocks the ATP-driven pump that returns Ca2+ from the cytosol into the sarcoplasmic reticulum. ATP supply, the neuromuscular junction, and the Ca2+ release channels are all normal. After a single nerve stimulus, which result is most likely?
- A. The fiber cannot contract because the sarcoplasmic reticulum cannot release Ca2+.
- B. The fiber contracts but relaxes abnormally slowly because Ca2+ stays in the cytosol and keeps troponin occupied. (correct)
- C. The fiber stays contracted because myosin heads cannot detach from actin without ATP.
- D. The fiber contracts weakly because acetylcholine cannot be broken down.
Release channels work, so the fiber contracts, but without Ca2+ reuptake the Ca2+ stays bound to troponin and cross-bridges keep cycling, which delays relaxation. Failure of myosin detachment (rigor) requires a lack of ATP, which is normal here.
Science · Human Anatomy and PhysiologyWhich of the following bones are part of the appendicular skeleton? Select all that apply.
- A. Clavicle (correct)
- B. Sternum
- C. Ilium (hip bone) (correct)
- D. Rib
- E. Humerus (correct)
- F. Mandible
The appendicular skeleton consists of the limbs and the girdles that attach them: the clavicle, ilium and humerus. The sternum, ribs and mandible belong to the axial skeleton, which forms the skull, vertebral column and thorax.
Science · Human Anatomy and PhysiologyA muscle biopsy from the calf of a long-distance runner is most likely to show a high proportion of fibers with which set of features?
- A. Small diameter, many mitochondria, high myoglobin content, and resistance to fatigue (correct)
- B. Large diameter, few mitochondria, abundant glycogen, and rapid fatigue
- C. Large diameter, many mitochondria, no myoglobin, and rapid fatigue
- D. Small diameter, few mitochondria, high myoglobin content, and rapid fatigue
Endurance activity relies on slow-twitch (oxidative) fibers, which have abundant mitochondria and myoglobin for aerobic ATP production and so resist fatigue. Choice B describes fast glycolytic fibers, which suit short bursts of power.

How to approach it

Anatomy and physiology is the largest part: 18 of the 44 scored Science questions. Learn each system's structures and what they do, then how systems work together.
For experiment questions, name the independent variable, the dependent variable and the control before reading the choices.
For chemistry, check units and charges: many wrong answers have the right number with the wrong sign or unit.
Pace: 60 minutes for 50 questions is 72 seconds each.

Practice under real conditions

The free TEAS diagnostic times every section like the real test and shows your score by sub-area. With the TEAS pass, you get three full-length timed mocks (170 questions each) and the full practice bank.

See where you stand in 49 minutes

The free diagnostic has 40 questions across all four sections, timed like the real test, and a report with your score for each sub-area. No account needed.

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Questions

How many Science questions are on the TEAS?

50 questions in 60 minutes, of which 44 are scored: Human Anatomy & Physiology 18, Biology 9, Chemistry 8 and Scientific Reasoning 9 (ATI exam details).

What's the hardest part of TEAS Science?

Anatomy and physiology is the biggest job: it's the largest share and covers every body system. The score report shows your result by sub-area so you can see where you stand.

Are there select-all-that-apply questions in Science?

Yes, multiple select is one of the TEAS question types (ATI). Here, as on the real test, you need every correct choice and no wrong one.

Keep practicing

Free TEAS practice testFree TEAS 7 practice questions from all four sections with answers and explanations, then a free timed diagnostic with your score by sub-area.Practice →TEAS Anatomy and Physiology practice questionsFree TEAS Anatomy and Physiology practice questions with answers and explanations: every body system, from cardiovascular to endocrine.Practice →TEAS Biology practice questionsFree TEAS Biology practice questions with answers and explanations: cells, macromolecules, DNA, cell division and genetics.Practice →TEAS Chemistry practice questionsFree TEAS Chemistry practice questions with answers and explanations: atoms, bonds, reactions, solutions, acids and bases.Practice →TEAS Scientific Reasoning practice questionsFree TEAS Scientific Reasoning practice questions with answers and explanations: experimental design, variables, controls and data.Practice →TEAS 7 test formatWhat's on the ATI TEAS 7: 170 questions in 209 minutes across four sections, the question types, the calculator and the rules on going back.Practice →

Sources

Updated November 6, 2026