Free TEAS 7 Science Practice Test 6 — 30 Questions With Full Explanations

Question 1. Anatomy & Physiology easy

Which type of muscle tissue is involuntary, lacks visible striations, and is found in the walls of blood vessels and hollow organs?

• A. Smooth muscle (correct)
• B. Skeletal muscle
• C. Cardiac muscle
• D. Striated voluntary muscle

Explanation: Smooth muscle is non-striated and involuntary, contracting slowly to move contents through hollow organs such as blood vessels, the stomach, and the bladder. Skeletal muscle is voluntary and striated, while cardiac muscle is striated but involuntary and confined to the heart.

Question 2. Anatomy & Physiology easy

Which tube carries urine from the kidney to the urinary bladder?

• A. Urethra
• B. Renal pelvis
• C. Collecting duct
• D. Ureter (correct)

Explanation: Urine formed in the nephrons drains into the renal pelvis and then travels down the ureter, a muscular tube, to the urinary bladder for storage. The urethra carries urine out of the body, and the collecting duct is part of the nephron rather than a tube leading to the bladder.

Question 3. Anatomy & Physiology easy

Which gland secretes melatonin, the hormone that helps regulate the sleep-wake cycle?

• A. Thyroid gland
• B. Pineal gland (correct)
• C. Adrenal gland
• D. Parathyroid gland

Explanation: The pineal gland, located deep in the brain, synthesizes melatonin in response to darkness and helps time the circadian sleep-wake cycle. The thyroid regulates metabolism, the adrenal glands produce stress hormones, and the parathyroid glands control blood calcium.

Question 4. Anatomy & Physiology medium

During the fight-or-flight response, which part of the adrenal gland secretes epinephrine to raise heart rate and mobilize energy stores?

• A. Adrenal medulla (correct)
• B. Adrenal cortex
• C. Anterior pituitary
• D. Pancreas

Explanation: The inner portion of the adrenal gland, the adrenal medulla, releases epinephrine and norepinephrine during stress, increasing heart rate, blood pressure, and blood glucose. The adrenal cortex secretes corticosteroids, the anterior pituitary controls other endocrine glands, and the pancreas regulates glucose.

Question 5. Anatomy & Physiology medium

Which organ is the primary source of erythropoietin, the hormone that stimulates red blood cell production?

• A. Liver
• B. Spleen
• C. Kidney (correct)
• D. Bone marrow

Explanation: The kidneys detect low blood oxygen and release erythropoietin, which circulates to the bone marrow and stimulates red blood cell production. The liver produces clotting factors and albumin, the spleen filters blood, and the bone marrow is where new red cells are made rather than a source of the hormone.

Question 6. Anatomy & Physiology medium

Which glands secrete parathyroid hormone, which raises blood calcium by promoting bone resorption and calcium reabsorption?

• A. Thyroid gland
• B. Parathyroid glands (correct)
• C. Adrenal cortex
• D. Pineal gland

Explanation: The four small parathyroid glands on the posterior surface of the thyroid release parathyroid hormone, which raises blood calcium by activating osteoclasts and increasing calcium reabsorption. The thyroid lowers calcium with calcitonin, the adrenal cortex produces corticosteroids, and the pineal gland secretes melatonin.

Question 7. Anatomy & Physiology medium

Which structure of the eye contains the photoreceptor cells that convert light energy into nerve impulses?

• A. Cornea
• B. Lens
• C. Iris
• D. Retina (correct)

Explanation: The retina, the innermost layer of the eye, contains the rods and cones that transduce light into electrical signals sent through the optic nerve to the brain. The cornea and lens focus incoming light, and the iris controls how much light enters through the pupil.

Question 8. Anatomy & Physiology medium

Which band of nerve fibers connects the left and right cerebral hemispheres, allowing the two sides of the brain to communicate?

• A. Cerebellum
• B. Thalamus
• C. Corpus callosum (correct)
• D. Medulla oblongata

Explanation: The corpus callosum is a thick tract of axons that transfers information between the two cerebral hemispheres so the brain can integrate sensory input and coordinate responses. The cerebellum coordinates movement and balance, the thalamus relays sensory signals, and the medulla controls autonomic functions such as breathing.

Question 9. Anatomy & Physiology medium

Which organ filters blood, removes aged red blood cells, and stores platelets and white blood cells?

• A. Spleen (correct)
• B. Thymus
• C. Gallbladder
• D. Appendix

Explanation: The spleen, the largest lymphatic organ, filters circulating blood, destroys worn-out red blood cells and recycles their iron, and stores platelets and lymphocytes. The thymus matures T lymphocytes, the gallbladder stores bile, and the appendix has only a minor immune role, so none of them filter blood.

Question 10. Anatomy & Physiology hard

Which enzyme, secreted by the chief cells of the stomach, begins the digestion of proteins into smaller peptides?

• A. Trypsin
• B. Amylase
• C. Lipase
• D. Pepsin (correct)

Explanation: Chief cells release pepsinogen, which stomach acid activates into pepsin, the enzyme that cleaves proteins into smaller peptides and begins protein digestion. Trypsin continues protein breakdown in the small intestine, amylase digests starch, and lipase digests fats, so the other enzymes act elsewhere.

Question 11. Anatomy & Physiology hard

In an adult human, which site is the primary location where red blood cells are produced?

• A. Yellow bone marrow
• B. Red bone marrow in spongy bone (correct)
• C. Spleen
• D. Liver

Explanation: In adults, red bone marrow inside the spongy bone of the axial skeleton and proximal limb bones is the main site of hematopoiesis, producing red blood cells, white blood cells, and platelets. Yellow marrow is mostly stored fat, and the spleen and liver do not normally produce red blood cells in adults.

Question 12. Anatomy & Physiology hard

Which type of glial cell lines the ventricles of the brain and produces cerebrospinal fluid?

• A. Ependymal cells (correct)
• B. Oligodendrocytes
• C. Microglia
• D. Astrocytes

Explanation: Ependymal cells line the brain ventricles and the central canal of the spinal cord, secrete cerebrospinal fluid, and help circulate it with their cilia. Oligodendrocytes form myelin in the central nervous system, microglia act as resident immune cells, and astrocytes support neurons and maintain the blood-brain barrier.

Question 13. Biology easy

Which sequence lists levels of biological organization from simplest to most complex?

• A. Organ, tissue, cell, organism
• B. Cell, tissue, organ, organism (correct)
• C. Tissue, cell, organ, organism
• D. Cell, organ, tissue, organism

Explanation: Cells are the smallest living units, similar cells group together into tissues, tissues combine to form organs, and organs work together within an organism. The correct hierarchy is therefore cell, tissue, organ, organism, and each other sequence scrambles that order.

Question 14. Biology medium

Which process converts atmospheric nitrogen gas into ammonia or other forms that plants can absorb and use?

• A. Denitrification
• B. Photosynthesis
• C. Nitrogen fixation (correct)
• D. Respiration

Explanation: Nitrogen-fixing bacteria in soil and in nodules of legume roots convert inert N2 gas into ammonia, which plants absorb to build proteins and nucleic acids. Denitrification returns nitrogen to the air, while photosynthesis and respiration cycle carbon rather than nitrogen.

Question 15. Biology medium

Which of the following is a component of the cytoskeleton, the network that maintains cell shape and supports intracellular transport?

• A. Ribosomes
• B. Lysosomes
• C. Peroxisomes
• D. Microtubules (correct)

Explanation: Microtubules, together with microfilaments and intermediate filaments, form the cytoskeleton, which maintains cell shape, anchors organelles, and provides tracks for motor proteins carrying vesicles. Ribosomes synthesize proteins, lysosomes digest cellular material, and peroxisomes break down fatty acids, none of which form structural networks.

Question 16. Biology medium

A woman who is a carrier of an X-linked recessive trait and an unaffected man have children. What is the probability that a son will express the trait?

• A. 50% (correct)
• B. 0%
• C. 25%
• D. 100%

Explanation: Each son receives his Y chromosome from the father and one X chromosome from the mother, who is heterozygous for the trait. There is a 50% chance the son inherits the recessive allele and a 50% chance he inherits the normal allele, so half of her sons express the trait.

Question 17. Biology hard

According to Mendel's law of independent assortment, alleles of different genes are distributed into gametes independently mainly because of

• A. Crossing over during prophase I
• B. The random alignment of homologous chromosome pairs during metaphase I of meiosis (correct)
• C. The separation of sister chromatids during anaphase II
• D. DNA replication during the S phase of the cell cycle

Explanation: Independent assortment arises from the random orientation of homologous chromosome pairs on the spindle during metaphase I, so alleles of genes on nonhomologous chromosomes combine freely into gametes. Crossing over rearranges alleles located on the same chromosome, and the other options describe events unrelated to how different genes sort into gametes.

Question 18. Biology hard

The forelimbs of humans, bats, and whales share a similar arrangement of bones despite very different functions. This similarity is best explained by

• A. Convergent evolution
• B. Acquired characteristics
• C. Common ancestry (correct)
• D. Geographic isolation

Explanation: Homologous structures such as the pentadactyl forelimb are inherited from a common ancestor and have diverged to serve different functions, providing evidence for evolution. Convergent evolution produces similar features with different evolutionary origins, and acquired characteristics and geographic isolation do not explain shared underlying anatomy.

Question 19. Chemistry easy

Which of the following is a physical property of a substance?

• A. Flammability
• B. Reactivity with acid
• C. Boiling point (correct)
• D. Ability to corrode metal

Explanation: A physical property, such as boiling point, density, or melting point, can be observed or measured without changing the chemical identity of the substance. Flammability, reactivity with acid, and corrosion all describe chemical behavior that converts the substance into new products.

Question 20. Chemistry medium

An ammonia molecule contains one nitrogen atom bonded to three hydrogen atoms (N = 14.0 g/mol, H = 1.0 g/mol). What is its molar mass?

• A. 15.0 g/mol
• B. 16.0 g/mol
• C. 18.0 g/mol
• D. 17.0 g/mol (correct)

Explanation: Ammonia contains one nitrogen atom and three hydrogen atoms, so its molar mass is 14.0 + 3(1.0) = 17.0 g/mol. The other values would result from miscounting the number of hydrogen atoms or from accidentally omitting the nitrogen atom from the calculation.

Question 21. Chemistry medium

A chemist weighs out 10.0 g of solid sodium hydroxide (NaOH) for a reaction. How many moles of NaOH does the sample contain? (Na = 23.0, O = 16.0, H = 1.0 g/mol)

• A. 0.25 mol (correct)
• B. 0.10 mol
• C. 0.40 mol
• D. 2.5 mol

Explanation: The molar mass of NaOH is 23.0 + 16.0 + 1.0 = 40.0 g/mol, so dividing the 10.0 g sample by 40.0 g/mol gives 0.25 mol. The other choices come from using an incorrect molar mass or from inverting the grams and moles in the division.

Question 22. Chemistry medium

What is the molarity of a solution prepared by dissolving 90.0 g of glucose (C6H12O6) in enough water to make 0.50 L of solution? (molar mass of C6H12O6 = 180.0 g/mol)

• A. 0.25 M
• B. 1.0 M (correct)
• C. 0.50 M
• D. 2.0 M

Explanation: Glucose has a molar mass of 180.0 g/mol, so 90.0 g equals 0.50 mol of glucose. Dividing 0.50 mol by the 0.50 L of solution gives a molarity of 1.0 mol/L, or 1.0 M. The other values result from misusing the mass, the volume, or both in the molarity calculation.

Question 23. Chemistry hard

According to the equation 2 H2O -> 2 H2 + O2, how many grams of oxygen gas are produced by the decomposition of 36.0 g of water? (H2O = 18.0 g/mol, O2 = 32.0 g/mol)

• A. 8.0 g
• B. 16.0 g
• C. 32.0 g (correct)
• D. 64.0 g

Explanation: A 36.0 g sample of water is 2.0 moles (36.0 divided by 18.0). The balanced equation shows that 2 moles of water yield 1 mole of oxygen, so 1.0 mole of O2 forms, which has a mass of 32.0 g. The other choices reflect incorrect mole ratios or mass conversions.

Question 24. Chemistry hard

Approximately how many molecules are present in 0.50 mol of carbon dioxide? (Avogadro's number = 6.022 x 10^23)

• A. 1.2 x 10^24
• B. 6.0 x 10^23
• C. 1.2 x 10^23
• D. 3.0 x 10^23 (correct)

Explanation: One mole of any substance contains 6.022 x 10^23 particles, so 0.50 mol contains 0.50 x 6.022 x 10^23 = 3.011 x 10^23 molecules, approximately 3.0 x 10^23. The other choices correspond to a full mole, twice a mole, or a miscounted fraction of a mole.

Question 25. Scientific Reasoning easy

Which statement is an observation rather than an inference?

• A. The leaf is green and measures 6 cm across (correct)
• B. The plant must be getting too much water
• C. The wilted flowers probably need fertilizer
• D. The animal is likely defending its territory

Explanation: An observation is a direct description of what is detected with the senses, such as the color and size of a leaf, while an inference is an interpretation built from observations. Judging that a plant is overwatered, that flowers need fertilizer, or that an animal is defending territory all require explanation beyond what is directly sensed.

Question 26. Scientific Reasoning medium

What is the main purpose of randomly assigning participants to treatment groups in an experiment?

• A. To ensure every participant receives the treatment
• B. To balance unknown confounding variables across groups (correct)
• C. To make the results easier to graph
• D. To guarantee the sample represents the whole population

Explanation: Random assignment spreads both known and unknown participant characteristics evenly across groups, so differences in outcomes are more likely to reflect the treatment than preexisting differences between people. It is not the same as random sampling, does not give everyone the treatment, and does not simplify graphing.

Question 27. Scientific Reasoning medium

Which type of graph is most appropriate for showing the distribution of a single continuous variable, such as the heights of 200 students?

• A. Line graph
• B. Pie chart
• C. Histogram (correct)
• D. Scatter plot

Explanation: A histogram groups continuous data into bins and shows how many values fall within each bin, making it ideal for displaying a distribution such as student heights. Line graphs show change over time, pie charts show parts of a whole, and scatter plots show the relationship between two different variables.

Question 28. Scientific Reasoning medium

A researcher plots experimental data and draws a line of best fit. Using that line to estimate a value that lies between two measured data points is called

• A. Extrapolation
• B. Correlation
• C. Standardization
• D. Interpolation (correct)

Explanation: Interpolation estimates a value within the range of the collected data, where the line of best fit is directly supported by nearby measured points. Extrapolation predicts beyond the data range and is less reliable, while correlation describes the strength of a relationship and standardization is a separate adjustment procedure.

Question 29. Scientific Reasoning hard

Why does averaging many repeated measurements of the same quantity reduce the impact of random error?

• A. Random errors tend to fall above and below the true value and cancel, so the mean approaches the true value (correct)
• B. Averaging converts systematic errors into random errors
• C. The measurements become more accurate because the instrument is recalibrated
• D. The median always equals the true value when many trials are averaged

Explanation: Random errors are about equally likely to be too high or too low, so they partially cancel out when many trials are averaged and the mean converges on the true value. Averaging does not remove a consistent systematic bias, does not recalibrate the instrument, and does not guarantee that the median matches the true value.

Question 30. Scientific Reasoning hard

Two students measure the length of a rod whose true length is 45.50 cm. Student A obtains 45.52, 45.48, and 45.51 cm. Student B obtains 45.9, 45.1, and 45.8 cm. Which conclusion is correct?

• A. Student B's measurements are more accurate but less precise
• B. Student A's measurements are both more precise and more accurate (correct)
• C. Student A's measurements are precise but less accurate than Student B's
• D. Student B's measurements are more precise but less accurate

Explanation: Student A's readings cluster tightly around the true value, so they are both precise, meaning low spread, and accurate, meaning close to 45.50 cm. Student B's readings vary by about 0.8 cm and stray farther from the true value, so they are neither more precise nor more accurate than Student A's.