What this section covers: Human anatomy and physiology, Biology, Chemistry, Scientific reasoning.
15 free practice questions
Click an answer: you see at once whether it is right, with the explanation.
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Question 1Gas exchange between inhaled air and the blood takes place mainly across the walls of the:
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Answer: C — Alveoli.
Alveoli are tiny air sacs whose very thin walls sit against pulmonary capillaries, so oxygen and carbon dioxide diffuse across them. The trachea and bronchi only conduct air, and the pleura is the membrane around the lungs.
Checked against: OpenStax Anatomy and Physiology 2e, 22.1 Organs and Structures of the Respiratory System; 22.4 Gas Exchange
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Question 2Which part of a typical neuron receives signals from other neurons and carries them toward the cell body?
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Answer: B — Dendrites.
Dendrites are branching extensions that receive input and conduct it toward the cell body. The axon carries signals away from the cell body to the axon terminals, and myelin insulates the axon.
Checked against: OpenStax Anatomy and Physiology 2e, 12.2 Nervous Tissue (Neuron structure)
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Question 3Where does most chemical digestion and absorption of nutrients take place?
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Answer: A — Small intestine.
The small intestine receives pancreatic enzymes and bile and has villi and microvilli that give a huge surface area, so most digestion and nutrient absorption happen there. The stomach starts protein digestion but absorbs little, and the esophagus only moves food.
Checked against: OpenStax Anatomy and Physiology 2e, 23.5 The Small and Large Intestines
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Question 4After a meal, blood glucose rises. Which hormone, released by beta cells of the pancreatic islets, lowers blood glucose?
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Answer: D — Insulin.
Insulin from beta cells promotes glucose uptake by body cells and its storage as glycogen, lowering blood glucose. Glucagon from alpha cells does the opposite, and cortisol and epinephrine also tend to raise blood glucose.
Checked against: OpenStax Anatomy and Physiology 2e, 17.9 The Endocrine Pancreas
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Question 5What is the functional unit of the kidney that filters blood and forms urine?
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Answer: C — Nephron.
Each kidney contains a very large number of nephrons, and each one filters blood at its glomerulus and then modifies the filtrate into urine. The renal pelvis and ureter only collect and carry urine, and a renal pyramid is a region of the medulla.
Checked against: OpenStax Anatomy and Physiology 2e, 25.4 Microscopic Anatomy of the Kidney
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Question 6Which cells secrete antibodies during an adaptive immune response?
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Answer: A — Plasma cells.
Activated B lymphocytes differentiate into plasma cells, which secrete large amounts of antibodies. Helper T cells coordinate the response but do not make antibodies, neutrophils are phagocytes, and erythrocytes carry oxygen.
Checked against: OpenStax Anatomy and Physiology 2e, 21.4 The Adaptive Immune Response: B-lymphocytes and Antibodies
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Question 7In pea plants, tall (T) is dominant over short (t). If two Tt plants are crossed, what fraction of the offspring is expected to be short?
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Answer: B — 1/4.
A Tt × Tt Punnett square gives TT, Tt, Tt and tt. Only tt (1 of 4 boxes) shows the recessive short phenotype; the other three are tall.
Checked against: OpenStax Biology 2e, 12.3 Laws of Inheritance
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Question 8In a DNA molecule, which base pairs with adenine?
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Answer: D — Thymine.
In DNA, adenine pairs with thymine and guanine pairs with cytosine. Uracil replaces thymine only in RNA.
Checked against: OpenStax Biology 2e, 14.2 DNA Structure and Sequencing
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Question 9Salivary amylase is an enzyme. To which class of macromolecules does it belong?
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Answer: A — Proteins.
Nearly all enzymes, including amylase, are proteins made of chains of amino acids folded into a specific shape. Amylase acts on carbohydrates (starch) but is not itself a carbohydrate.
Checked against: OpenStax Biology 2e, 3.4 Proteins (Types and functions)
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Question 10What is the pH of a neutral aqueous solution at 25 °C?
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Answer: C — 7.
At 25 °C pure water has equal hydrogen and hydroxide ion concentrations, giving a pH of 7. Values below 7 are acidic and values above 7 are basic.
Checked against: OpenStax Chemistry 2e, 14.2 pH and pOH
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Question 11Which set of coefficients balances the equation H2 + O2 → H2O?
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Answer: B — 2, 1, 2.
2 H2 + O2 → 2 H2O has 4 hydrogen atoms and 2 oxygen atoms on each side. The other sets leave hydrogen or oxygen unbalanced.
Checked against: OpenStax Chemistry 2e, 4.1 Writing and Balancing Chemical Equations
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Question 12Which of the following is a chemical change?
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Answer: D — An iron nail rusting.
Rusting forms a new substance (iron oxide), so it is a chemical change. Melting, boiling and dissolving change the state or mixture but not the identity of the substances.
Checked against: OpenStax Chemistry 2e, 1.3 Physical and Chemical Properties
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Question 13What is the SI base unit of mass?
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Answer: A — Kilogram.
The SI base unit of mass is the kilogram; the gram is a smaller unit (1/1,000 kg) formed with a metric prefix. The liter measures volume and the newton measures force.
Checked against: OpenStax Chemistry 2e, 1.4 Measurements (SI base units)
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Question 14Which statement is the best example of a scientific hypothesis?
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Answer: C — Plants given more light will grow taller than plants given less light..
A hypothesis is a testable, falsifiable prediction that can be checked by an experiment, like the statement about light and plant height. Personal opinions cannot be tested, science does not declare ideas permanently proven, and "Plants grow" makes no testable comparison.
Checked against: OpenStax Biology 2e, 1.1 The Science of Biology (hypothesis)
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Question 15A reaction takes 64 s at 10 °C, 32 s at 20 °C and 16 s at 30 °C. If the same pattern continues, how long should it take at 40 °C?
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Answer: B — 8 s.
Each 10 °C increase halves the reaction time (64, 32, 16), so the next value is 16 ÷ 2 = 8 s. Subtracting a constant amount would not fit the data.
Checked against: ATI TEAS Version 7 content outline, Science, S.4.3 Predict relationships among events, objects, and processes
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