Free TEAS 7 Science Practice Test 2 — 30 Questions With Full Explanations

Question 1. Anatomy & Physiology easy

Which chamber of the heart receives oxygenated blood returning from the lungs?

• A. Left atrium (correct)
• B. Right ventricle
• C. Right atrium
• D. Left ventricle

Explanation: Oxygenated blood from the lungs enters the left atrium through the pulmonary veins. The right atrium receives deoxygenated blood from the body, and the ventricles eject blood rather than receiving it from veins, so those choices do not fit the chamber that receives pulmonary blood.

Question 2. Anatomy & Physiology medium

Which structure normally sets the pace of the heartbeat by generating spontaneous electrical impulses?

• A. Purkinje fibers
• B. Sinoatrial node (correct)
• C. Atrioventricular node
• D. Vagus nerve

Explanation: The sinoatrial node in the right atrium fires first in every cardiac cycle, so it sets the heart rate. The atrioventricular node, Purkinje fibers, and vagus nerve conduct, delay, or adjust the signal after it has already been started, so none of them initiates the normal rhythm.

Question 3. Anatomy & Physiology hard

Which blood vessels offer the greatest resistance to blood flow and therefore exert the most control over systemic blood pressure?

• A. Venules
• B. Capillaries
• C. Arterioles (correct)
• D. Aorta

Explanation: Arterioles are small muscular vessels whose constriction and dilation change total peripheral resistance, strongly influencing blood pressure. Capillaries are exchange vessels with little resistance, the aorta is a large elastic conduit, and venules collect blood at low pressure, so arterioles are the main resistance vessels.

Question 4. Anatomy & Physiology easy

Which structure closes over the opening of the larynx during swallowing to keep food and liquid out of the airway?

• A. Glottis
• B. Hyoid bone
• C. Uvula
• D. Epiglottis (correct)

Explanation: The epiglottis is the flexible flap that folds down over the laryngeal opening during swallowing, directing food into the esophagus. The uvula hangs from the soft palate, the glottis is the vocal opening itself, and the hyoid bone anchors tongue muscles, so none of those seals off the airway.

Question 5. Anatomy & Physiology medium

Which muscle provides most of the force for quiet, effortless inspiration?

• A. Diaphragm (correct)
• B. Sternocleidomastoid
• C. External intercostals
• D. Rectus abdominis

Explanation: During quiet breathing the diaphragm supplies the bulk of the inspiratory effort by flattening and enlarging the chest cavity. The external intercostals assist mainly in deeper breaths, the sternocleidomastoid is an accessory neck muscle, and the rectus abdominis is an expiratory abdominal muscle, so the diaphragm is primary.

Question 6. Anatomy & Physiology medium

Which organ produces bile, the fluid that emulsifies fats in the small intestine?

• A. Stomach
• B. Liver (correct)
• C. Gallbladder
• D. Pancreas

Explanation: Hepatic cells in the liver synthesize bile continuously, and the gallbladder merely stores and concentrates that bile; it does not make it. The pancreas secretes digestive enzymes and bicarbonate, and the stomach produces acid and pepsin, so liver is the only correct source of bile.

Question 7. Anatomy & Physiology easy

Which muscular tube carries swallowed food from the pharynx down to the stomach?

• A. Trachea
• B. Larynx
• C. Esophagus (correct)
• D. Duodenum

Explanation: The esophagus is the muscular tube connecting the pharynx to the stomach, moving food onward by peristalsis. The trachea and larynx are airway structures, and the duodenum is the first segment of the small intestine, so none of those transports food from the throat to the stomach.

Question 8. Anatomy & Physiology medium

Which part of the brain is primarily responsible for coordinating voluntary movements and maintaining balance and posture?

• A. Medulla oblongata
• B. Hypothalamus
• C. Cerebrum
• D. Cerebellum (correct)

Explanation: The cerebellum fine-tunes movement, balance, and posture by comparing intended motion with actual motion. The cerebrum handles conscious thought and planning, the medulla controls automatic functions such as breathing, and the hypothalamus manages homeostasis, so cerebellum best matches the coordination role.

Question 9. Anatomy & Physiology hard

Which cells produce the myelin sheath that insulates axons in the peripheral nervous system?

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

Explanation: Schwann cells wrap around peripheral axons to form myelin, which speeds impulse conduction. Oligodendrocytes perform the same task in the central nervous system instead, astrocytes support the blood-brain barrier, and microglia act as immune cells, so only Schwann cells myelinate peripheral nerves.

Question 10. Anatomy & Physiology medium

Which anterior pituitary hormone stimulates the adrenal cortex to release cortisol?

• A. Insulin
• B. Adrenocorticotropic hormone (ACTH) (correct)
• C. Antidiuretic hormone (ADH)
• D. Thyroid-stimulating hormone (TSH)

Explanation: ACTH from the anterior pituitary targets the adrenal cortex and drives cortisol secretion during stress. ADH acts on the kidneys to conserve water, TSH stimulates the thyroid gland, and insulin is made by the pancreas to lower blood glucose, so none of these hormones triggers cortisol release.

Question 11. Anatomy & Physiology hard

Which white blood cell is the main phagocyte that engulfs pathogens, dead cells, and debris during an infection?

• A. Platelet
• B. Red blood cell
• C. Macrophage (correct)
• D. B lymphocyte

Explanation: Macrophages are professional phagocytes that engulf and digest pathogens and cellular debris as a first line of immune defense. B lymphocytes instead produce antibodies, red blood cells carry oxygen, and platelets help form clots, so macrophage uniquely matches the engulf-and-destroy role.

Question 12. Anatomy & Physiology medium

Which vessel carries blood away from the glomerulus after filtration has occurred?

• A. Renal artery
• B. Afferent arteriole
• C. Inferior vena cava
• D. Efferent arteriole (correct)

Explanation: Blood leaves the glomerulus through the efferent arteriole, which then splits into peritubular capillaries around the tubules. The afferent arteriole delivers blood into the glomerulus, the renal artery supplies the whole kidney, and the inferior vena cava collects systemic venous blood, so the efferent arteriole drains the glomerulus.

Question 13. Biology easy

Which organelle is the site where proteins are assembled from amino acids?

• A. Ribosome (correct)
• B. Cell membrane
• C. Nucleus
• D. Lysosome

Explanation: Ribosomes link amino acids into polypeptide chains during translation, so they are the protein factories of the cell. Lysosomes digest cellular waste, the nucleus stores genetic information, and the cell membrane controls what enters and leaves, so none of those builds proteins.

Question 14. Biology medium

During which phase of mitosis do sister chromatids separate and move toward opposite poles of the cell?

• A. Telophase
• B. Anaphase (correct)
• C. Prophase
• D. Metaphase

Explanation: In anaphase the centromeres split and sister chromatids are pulled to opposite ends by spindle fibers. Prophase condenses the chromosomes, metaphase aligns them at the equator, and telophase rebuilds the nuclear envelopes, so chromatid separation occurs only in anaphase.

Question 15. Biology medium

Which process divides one diploid parent cell into two genetically identical diploid daughter cells?

• A. Meiosis
• B. Fertilization
• C. Mitosis (correct)
• D. Binary fission

Explanation: Mitosis produces two genetically identical diploid cells, which is how the body grows and repairs tissues. Meiosis yields four genetically distinct haploid gametes, binary fission is the prokaryotic division process, and fertilization fuses gametes, so only mitosis matches the description.

Question 16. Biology hard

Crossing over, which exchanges genetic material between homologous chromosomes, occurs during which stage?

• A. Metaphase II of meiosis
• B. Anaphase of mitosis
• C. Telophase I of meiosis
• D. Prophase I of meiosis (correct)

Explanation: In prophase I, homologous chromosomes pair up and swap segments, creating new combinations of alleles. Mitosis has no pairing of homologous chromosomes, metaphase II aligns already-haploid chromosomes, and telophase I ends the first division, so crossing over is confined to prophase I.

Question 17. Biology medium

Which molecule carries the genetic message from DNA in the nucleus to the ribosomes in the cytoplasm?

• A. Messenger RNA (mRNA) (correct)
• B. Transfer RNA (tRNA)
• C. Ribosomal RNA (rRNA)
• D. DNA polymerase

Explanation: mRNA is transcribed from DNA and carries the protein-building instructions to ribosomes in the cytoplasm. tRNA delivers amino acids one at a time, rRNA is a structural component of ribosomes, and DNA polymerase copies DNA, so mRNA is the molecule that carries the message.

Question 18. Biology easy

During photosynthesis, plants take in which gas from the air to build glucose?

• A. Hydrogen
• B. Carbon dioxide (correct)
• C. Nitrogen
• D. Oxygen

Explanation: Plants fix carbon dioxide from the air in the Calvin cycle to build glucose. Oxygen is released as a byproduct of the light reactions, nitrogen is not fixed by photosynthesis, and hydrogen gas is not taken up by leaves, so carbon dioxide is the gas consumed.

Question 19. Chemistry easy

Which subatomic particle determines the atomic number and therefore the identity of an element?

• A. Electron
• B. Neutron
• C. Proton (correct)
• D. Photon

Explanation: The number of protons defines the element, and changing that number changes the element entirely. Neutrons change mass but not identity, electrons can be gained or lost without changing the element, and photons are particles of light, so protons alone set the atomic number.

Question 20. Chemistry medium

An atom has 11 protons, 12 neutrons, and 11 electrons. What is its mass number?

• A. 12
• B. 22
• C. 11
• D. 23 (correct)

Explanation: The mass number is the total number of protons plus neutrons, so 11 plus 12 equals 23. The value 11 counts only the protons, 12 counts only the neutrons, and 22 confuses protons plus electrons, so 23 is the only correct total.

Question 21. Chemistry hard

Water molecules attract one another through hydrogen bonds because

• A. oxygen pulls the shared electrons closer, giving the molecule partial charges and making it polar (correct)
• B. each hydrogen carries a full positive charge that attracts neighboring oxygens
• C. electrons are transferred completely from hydrogen to oxygen, forming ions
• D. hydrogen and oxygen share electrons equally, so the molecule is nonpolar

Explanation: Oxygen is more electronegative than hydrogen, so it draws the shared electrons closer and leaves partial negative and positive poles that attract other molecules. Complete electron transfer would form ions, full positive charges overstate the polarity, and equal sharing would make water nonpolar, so the partial-charge description is correct.

Question 22. Chemistry medium

What is the molar mass of sulfuric acid (H2SO4)? (H = 1.0 g/mol, S = 32.1 g/mol, O = 16.0 g/mol)

• A. 49.0 g/mol
• B. 98.1 g/mol (correct)
• C. 114.1 g/mol
• D. 82.1 g/mol

Explanation: Two hydrogens (2.0), one sulfur (32.1), and four oxygens (64.0) add to 98.1 g/mol. The 49.0 value is half the total, 82.1 omits one oxygen, and 114.1 adds an extra oxygen, so 98.1 g/mol is the correct molar mass of sulfuric acid.

Question 23. Chemistry hard

A 0.10 M solution of hydrochloric acid dissociates completely. What is the pH of this solution?

• A. 5
• B. 7
• C. 1 (correct)
• D. 13

Explanation: For a strong acid that dissociates fully, the hydrogen ion concentration equals 0.10 M, and pH is the negative log of that concentration, giving 1. The value 7 confuses the acid with neutrality, 13 describes a strong base, and 5 misplaces the decimal, so pH 1 is correct.

Question 24. Chemistry easy

How many milliliters are in 1.5 liters?

• A. 15 mL
• B. 15,000 mL
• C. 150 mL
• D. 1,500 mL (correct)

Explanation: One liter equals 1,000 milliliters, so 1.5 liters is 1.5 times 1,000, or 1,500 mL. The values 15 and 150 multiply by the wrong factors, and 15,000 would result from multiplying by 10,000, so 1,500 mL is the correct conversion.

Question 25. Scientific Reasoning easy

A researcher wants to test whether different amounts of fertilizer affect bean plant height. What is the independent variable?

• A. The amount of fertilizer applied (correct)
• B. The number of days of growth
• C. The height of the plants
• D. The type of soil used

Explanation: The independent variable is what the researcher deliberately changes, which here is the fertilizer amount. Plant height is the measured outcome, while soil type and growth time are controlled variables held constant, so only the fertilizer amount is manipulated.

Question 26. Scientific Reasoning medium

In a trial testing a new headache medication, half the participants receive the drug and half receive an inactive tablet. What is the purpose of the inactive-tablet group?

• A. To provide a second dose of the same drug
• B. To serve as a control that accounts for the expectation of receiving treatment (correct)
• C. To double the number of participants in the study
• D. To let researchers identify who took the drug

Explanation: The placebo group goes through the same routine as the treatment group but without the active ingredient, isolating the drug's true effect from the psychological benefit of being treated. It is not a second dose, a way to enlarge the sample, or a method of revealing who received the drug.

Question 27. Scientific Reasoning medium

Which statement best describes a scientific theory?

• A. A personal opinion that has not been examined
• B. A specific prediction of what will happen in a trial
• C. A broad, well-supported explanation that organizes many observations and has survived repeated testing (correct)
• D. A single untested guess about one experiment

Explanation: A scientific theory is a comprehensive explanation supported by a large body of evidence, such as cell theory or germ theory. A guess, a specific prediction, or an unexamined opinion describes a hypothesis or speculation, not a theory, so the well-supported explanation is correct.

Question 28. Scientific Reasoning hard

In a double-blind drug trial, neither the participants nor the researchers know who received the drug until the study ends. This design mainly controls for

• A. variation in the participants' ages
• B. differences in the participants' diets
• C. errors in measuring the dependent variable
• D. bias caused by the expectations of participants and researchers (correct)

Explanation: Blinding prevents expectations from influencing outcomes or their interpretation, because neither side knows the group assignments. Measurement errors, diet differences, and age variation are separate threats handled by calibration, standardization, or randomization rather than by blinding, so expectation bias is the target.

Question 29. Scientific Reasoning medium

A technician weighs the same sample five times and obtains nearly identical readings each time. This repeatability indicates

• A. high reliability of the measurement procedure (correct)
• B. that the sample is changing mass during the session
• C. that the measurements must also be accurate
• D. that the balance is measuring the wrong property

Explanation: Consistent repeated results show that the procedure is reliable, meaning measurements are repeatable. Reliability does not guarantee accuracy, because a calibrated-but-offset balance can be consistently wrong, and stable readings argue against a changing sample or a wrong property, so reliability is the correct conclusion.

Question 30. Scientific Reasoning hard

A researcher reports a very large standard deviation in reaction times collected from a group of participants. This statistic indicates that

• A. the mean reaction time is definitely incorrect
• B. the individual reaction times are widely spread around the mean (correct)
• C. every reaction time is identical
• D. the experiment must have been run in error

Explanation: Standard deviation measures how much individual values scatter around the mean, so a large value means wide spread among participants. It does not by itself make the mean incorrect, identical values would give a tiny deviation, and spread alone does not prove an experimental error.