51 Science Practice Questions & Answers
Every Science practice question from the TEAS Practice Test, with the correct answer and a short explanation.
Start practice test →1. Which chamber of the heart pumps oxygenated blood out to the entire body through the aorta?
- A.Left atrium
- B.Left ventricle✓ Answer
- C.Right ventricle
- D.Right atrium
The left ventricle has the thickest muscular wall and pumps oxygenated blood into the aorta for systemic circulation.
2. What is the primary function of red blood cells (erythrocytes)?
- A.Fighting infection
- B.Forming blood clots
- C.Producing antibodies
- D.Transporting oxygen via hemoglobin✓ Answer
Red blood cells carry oxygen bound to the iron-containing protein hemoglobin; white cells fight infection and platelets aid clotting.
3. Which organ system includes the epidermis, dermis, hair, and nails, and serves as the body's first line of defense?
- A.Muscular system
- B.Lymphatic system
- C.Endocrine system
- D.Integumentary system✓ Answer
The integumentary system (skin, hair, nails) forms a physical barrier and is the body's first line of defense against pathogens.
4. In which part of the respiratory system does gas exchange between air and blood occur?
- A.Alveoli✓ Answer
- B.Bronchi
- C.Trachea
- D.Larynx
Gas exchange occurs across the thin walls of the alveoli, tiny air sacs surrounded by capillaries in the lungs.
5. What is the functional filtering unit of the kidney?
- A.Alveolus
- B.Neuron
- C.Villus
- D.Nephron✓ Answer
The nephron is the microscopic functional unit of the kidney where blood is filtered and urine is formed.
6. Which organelle is the primary site of cellular respiration (ATP production) in eukaryotic cells?
- A.Ribosome
- B.Mitochondrion✓ Answer
- C.Nucleus
- D.Golgi apparatus
The mitochondrion generates most of the cell's ATP (adenosine triphosphate) through aerobic cellular respiration.
7. During DNA replication, adenine (A) always pairs with which base?
- A.Uracil (U)
- B.Guanine (G)
- C.Thymine (T)✓ Answer
- D.Cytosine (C)
In DNA, complementary base pairing joins adenine with thymine (A–T) and cytosine with guanine (C–G).
8. On the pH scale, a solution with a pH of 3 is best described as:
- A.Neutral
- B.A buffer
- C.Basic (alkaline)
- D.Acidic✓ Answer
The pH scale runs 0–14; values below 7 are acidic, 7 is neutral, and above 7 is basic, so pH 3 is acidic.
9. In the atom, which subatomic particle carries a negative electrical charge?
- A.Proton
- B.Electron✓ Answer
- C.Nucleus
- D.Neutron
Electrons carry a negative charge, protons are positive, and neutrons have no charge.
10. Which type of chemical bond forms when electrons are transferred from a metal to a nonmetal, creating oppositely charged ions?
- A.Covalent bond
- B.Hydrogen bond
- C.Metallic bond
- D.Ionic bond✓ Answer
An ionic bond forms by the transfer of electrons, producing oppositely charged ions that attract each other; covalent bonds share electrons.
11. In a controlled scientific experiment, what is the independent variable?
- A.The factor that is measured as the outcome
- B.The factor the researcher deliberately changes✓ Answer
- C.The group receiving no treatment
- D.A factor kept constant across all groups
The independent variable is the one the researcher deliberately manipulates; the dependent variable is what is measured in response.
12. Which endocrine gland secretes insulin to lower blood glucose levels?
- A.Adrenal gland
- B.Pituitary gland
- C.Thyroid
- D.Pancreas✓ Answer
The beta cells of the pancreas secrete insulin, which lowers blood glucose by promoting its uptake into cells.
13. In standard anatomical position, which directional term means 'toward the head' or 'above'?
- A.Inferior (caudal)
- B.Distal
- C.Posterior
- D.Superior (cranial)✓ Answer
Superior (cranial) means toward the head or upper part of the body; inferior means toward the feet.
14. Which directional term describes a structure that is farther from the point of attachment to the trunk, such as the wrist relative to the elbow?
- A.Proximal
- B.Medial
- C.Distal✓ Answer
- D.Superficial
Distal means farther from the trunk or point of attachment; proximal means closer to it. The wrist is distal to the elbow.
15. The maintenance of a stable internal environment despite external changes is called:
- A.Metabolism
- B.Homeostasis✓ Answer
- C.Diffusion
- D.Respiration
Homeostasis is the body's ability to maintain stable internal conditions (temperature, pH, glucose) through feedback mechanisms.
16. Which structural and functional unit of the nervous system transmits electrical impulses?
- A.Nephron
- B.Alveolus
- C.Sarcomere
- D.Neuron✓ Answer
The neuron is the basic unit of the nervous system; it conducts electrical impulses via its axon and dendrites.
17. Which part of the brain controls balance, coordination, and fine motor movement?
- A.Cerebrum
- B.Medulla oblongata
- C.Cerebellum✓ Answer
- D.Hypothalamus
The cerebellum coordinates balance, posture, and fine, smooth voluntary movements.
18. Where does the majority of nutrient absorption occur in the digestive system?
- A.Stomach
- B.Esophagus
- C.Small intestine✓ Answer
- D.Large intestine
Most nutrient absorption occurs in the small intestine, whose villi and microvilli greatly increase surface area.
19. Which type of muscle tissue is striated, voluntary, and attached to bones?
- A.Smooth muscle
- B.Cardiac muscle
- C.Skeletal muscle✓ Answer
- D.Connective tissue
Skeletal muscle is striated and under voluntary control; smooth muscle is involuntary and non-striated, and cardiac muscle is striated but involuntary.
20. What is the primary function of red bone marrow found inside certain bones?
- A.Storing fat
- B.Producing blood cells (hematopoiesis)✓ Answer
- C.Secreting hormones
- D.Cushioning joints
Red bone marrow is the site of hematopoiesis, producing red blood cells, white blood cells, and platelets.
21. Which cells of the immune system produce antibodies to target specific pathogens?
- A.B lymphocytes (B cells)✓ Answer
- B.Red blood cells
- C.Platelets
- D.Osteocytes
B lymphocytes differentiate into plasma cells that produce antibodies, a key part of the adaptive immune response.
22. In the female reproductive system, where does fertilization of an egg by sperm normally occur?
- A.Uterus
- B.Ovary
- C.Cervix
- D.Fallopian tube (oviduct)✓ Answer
Fertilization normally occurs in the fallopian tube; the resulting zygote then travels to the uterus to implant.
23. Which blood vessels carry blood away from the heart?
- A.Veins
- B.Arteries✓ Answer
- C.Capillaries
- D.Venules
Arteries carry blood away from the heart; veins return blood to the heart. Capillaries connect the two and allow exchange.
24. Which muscle contracts and flattens to draw air into the lungs during inhalation?
- A.Diaphragm✓ Answer
- B.Biceps
- C.Cardiac muscle
- D.Trachea
The diaphragm contracts and moves downward during inhalation, increasing thoracic volume and drawing air into the lungs.
25. Which organelle contains a cell's genetic material (DNA) and directs cell activities?
- A.Lysosome
- B.Mitochondrion
- C.Cell membrane
- D.Nucleus✓ Answer
The nucleus houses the cell's DNA and controls gene expression, directing growth, metabolism, and reproduction.
26. The movement of water across a selectively permeable membrane from low to high solute concentration is called:
- A.Active transport
- B.Osmosis✓ Answer
- C.Phagocytosis
- D.Exocytosis
Osmosis is the passive diffusion of water across a membrane toward the region of higher solute concentration; it requires no energy.
27. Which process of cell division produces two genetically identical diploid daughter cells for growth and repair?
- A.Meiosis
- B.Fertilization
- C.Mitosis✓ Answer
- D.Transcription
Mitosis produces two identical diploid cells for growth and repair; meiosis produces four genetically varied haploid gametes.
28. In a Punnett square cross of two heterozygous parents (Bb x Bb), what fraction of offspring is expected to show the recessive phenotype?
- A.1/4✓ Answer
- B.1/2
- C.3/4
- D.All of them
A Bb x Bb cross yields a 1:2:1 genotype ratio (BB:Bb:bb), so only bb (1/4) shows the recessive phenotype.
29. Which nitrogenous base is found in RNA but not in DNA, replacing thymine?
- A.Adenine
- B.Cytosine
- C.Uracil✓ Answer
- D.Guanine
RNA uses uracil (U) in place of the thymine (T) found in DNA; both pair with adenine.
30. Which class of macromolecules serves as the primary structural component of cell membranes and stores energy long-term?
- A.Carbohydrates
- B.Nucleic acids
- C.Proteins
- D.Lipids✓ Answer
Lipids (including phospholipids) form the cell membrane's bilayer and store energy long-term as fats.
31. What is the primary role of an enzyme in a biochemical reaction?
- A.To provide energy for the reaction
- B.To lower the activation energy and speed up the reaction✓ Answer
- C.To become permanently consumed by the reaction
- D.To raise the temperature of the cell
Enzymes are biological catalysts that lower activation energy to speed up reactions; they are not consumed and can be reused.
32. The atomic number of an element is equal to the number of what?
- A.Neutrons
- B.Protons✓ Answer
- C.Electrons plus neutrons
- D.Protons plus neutrons
The atomic number equals the number of protons in an atom's nucleus, which defines the element. Protons plus neutrons give the mass number.
33. On the periodic table, elements in the same vertical column (group) tend to share what?
- A.The same number of neutrons
- B.The same atomic mass
- C.Similar chemical properties✓ Answer
- D.The same number of energy levels
Elements in the same group have the same number of valence electrons, giving them similar chemical properties.
34. In the chemical reaction 2H2 + O2 -> 2H2O, the substances on the left side (H2 and O2) are called the:
- A.Products
- B.Catalysts
- C.Solvents
- D.Reactants✓ Answer
Reactants are the starting substances on the left of the arrow; products are formed on the right (here, water).
35. Which state of matter has a definite volume but takes the shape of its container?
- A.Solid
- B.Liquid✓ Answer
- C.Gas
- D.Plasma
A liquid has a definite volume but no fixed shape, so it conforms to its container; a solid keeps both shape and volume, and a gas keeps neither.
36. What is the correct first step of the scientific method?
- A.Make an observation and ask a question✓ Answer
- B.Draw a conclusion
- C.Analyze the data
- D.Form a theory
The scientific method begins with observation and a question, which then leads to forming a testable hypothesis.
37. In an experiment testing how fertilizer amount affects plant height, the plant height is the:
- A.Independent variable
- B.Dependent variable✓ Answer
- C.Control group
- D.Constant
The dependent variable is the measured outcome (plant height); the amount of fertilizer is the independent variable being changed.
38. In a controlled experiment, what is the purpose of the control group?
- A.To receive the highest dose of treatment
- B.To provide a baseline for comparison without the experimental treatment✓ Answer
- C.To be measured only at the end
- D.To change the independent variable
The control group does not receive the experimental treatment and serves as a baseline to compare against the experimental group.
39. Which type of feedback mechanism reverses a change to restore homeostasis, such as sweating to lower body temperature?
- A.Positive feedback
- B.Feedforward
- C.Negative feedback✓ Answer
- D.Passive transport
Negative feedback counteracts a change to return the body to its set point (e.g., sweating cools an overheated body); positive feedback amplifies a change.
40. The liver produces bile, which is stored in the gallbladder and helps digest what type of nutrient?
- A.Proteins
- B.Carbohydrates
- C.Fats (lipids)✓ Answer
- D.Nucleic acids
Bile emulsifies fats, breaking large fat globules into smaller droplets so lipase enzymes can digest them more efficiently.
41. In a negative feedback loop regulating blood glucose, what happens immediately after blood sugar rises following a meal?
- A.The kidneys increase glucose reabsorption
- B.The pancreas releases insulin, which lowers blood glucose✓ Answer
- C.The liver stops storing glucose as glycogen
- D.The pancreas releases glucagon, which raises blood glucose
A negative feedback loop counteracts a change to restore the set point: when blood glucose rises, beta cells of the pancreas secrete insulin, which drives glucose into cells and promotes glycogen storage, bringing the level back down.
Source: ATI TEAS 7 Science outline — Human anatomy & physiology: endocrine system / negative feedbackReport a problem with this question
42. Which of the following is a feature of the innate immune response rather than the adaptive immune response?
- A.Long-lasting immunity after exposure to a pathogen
- B.Antibody production tailored to a specific antigen
- C.A rapid, nonspecific response such as inflammation and phagocytosis✓ Answer
- D.Production of memory B cells specific to one pathogen
The innate immune system is the body's first line of defense: it responds quickly and nonspecifically to any pathogen through barriers, inflammation, and phagocytes, whereas memory and antigen-specific antibodies are hallmarks of the slower adaptive response.
Source: ATI TEAS 7 Science outline — Human anatomy & physiology: immune system (innate vs. adaptive immunity)Report a problem with this question
43. A solution has a hydrogen ion concentration ten times greater than a solution with a pH of 5. What is the pH of this solution?
- A.15
- B.4✓ Answer
- C.6
- D.50
The pH scale is logarithmic (base 10), so each whole-number decrease in pH represents a tenfold increase in hydrogen ion concentration; a solution ten times more acidic than pH 5 therefore has a pH of 4.
Source: ATI TEAS 7 Science outline — Chemistry: acids, bases, and the pH scaleReport a problem with this question
44. Nucleotides are the monomers that build which class of macromolecule?
- A.Carbohydrates
- B.Proteins
- C.Nucleic acids (DNA and RNA)✓ Answer
- D.Lipids
Each macromolecule has a characteristic monomer: nucleotides polymerize into nucleic acids (DNA and RNA), while amino acids build proteins, monosaccharides build carbohydrates, and lipids are not true polymers.
Source: ATI TEAS 7 Science outline — Biology: macromolecules and their monomersReport a problem with this question
45. Two heterozygous pea plants for a trait (Aa x Aa) are crossed, where A is dominant. What phenotypic ratio is expected in the offspring?
- A.3 dominant : 1 recessive✓ Answer
- B.1 dominant : 1 recessive
- C.9 dominant : 3 recessive
- D.All dominant
A monohybrid cross of two heterozygotes yields genotypes in a 1 AA : 2 Aa : 1 aa ratio; because A masks a, three of the four offspring show the dominant phenotype, giving a 3:1 phenotypic ratio.
Source: ATI TEAS 7 Science outline — Biology: Mendelian genetics (monohybrid cross, Punnett square)Report a problem with this question
46. As you move from left to right across a period (row) of the periodic table, what generally happens to atomic radius?
- A.It stays the same because the shell number is unchanged
- B.It decreases because increasing nuclear charge pulls electrons closer✓ Answer
- C.It increases because protons repel one another
- D.It increases because more electron shells are added
Across a period, protons are added to the nucleus while electrons fill the same energy level; the greater nuclear charge pulls the electron cloud inward, so atomic radius decreases from left to right.
Source: ATI TEAS 7 Science outline — Chemistry: atomic structure and periodic trendsReport a problem with this question
47. Which of the following is a chemical change rather than a physical change?
- A.Iron rusting to form iron oxide✓ Answer
- B.Chopping wood into smaller pieces
- C.Ice melting into liquid water
- D.Salt dissolving in water
A chemical change produces one or more new substances with different chemical identities; rusting combines iron and oxygen to form iron oxide, whereas melting, dissolving, and chopping only change form or state without creating a new substance.
Source: ATI TEAS 7 Science outline — Chemistry: physical vs. chemical changesReport a problem with this question
48. In an experiment testing how fertilizer amount affects plant height, which factor is the independent variable?
- A.The type of soil used
- B.The amount of sunlight given
- C.The height the plants reach
- D.The amount of fertilizer applied✓ Answer
The independent variable is the factor the researcher deliberately manipulates; here that is the amount of fertilizer, while plant height is the dependent variable (the measured outcome) and soil and sunlight are controlled constants.
Source: ATI TEAS 7 Science outline — Scientific reasoning: experimental design (independent, dependent, and controlled variables)Report a problem with this question
49. When a person becomes too warm, the body sweats to cool down. This is an example of what process?
- A.Passive diffusion of heat into cells
- B.A chemical change in the skin cells
- C.Homeostasis maintaining a stable internal temperature✓ Answer
- D.Metabolism generating extra body heat
Homeostasis is the maintenance of a stable internal environment despite external change; sweating uses evaporative cooling to bring body temperature back toward its set point, an example of thermoregulation.
Source: ATI TEAS 7 Science outline — Human anatomy & physiology: homeostasis and thermoregulationReport a problem with this question
50. Two atoms of the same element that have different numbers of neutrons are called what?
- A.Ions
- B.Isomers
- C.Allotropes
- D.Isotopes✓ Answer
An element is defined by its number of protons (atomic number); atoms of that element with different neutron counts have different mass numbers and are called isotopes, whereas ions differ in electron number and carry a charge.
Source: ATI TEAS 7 Science outline — Chemistry: atomic structure (isotopes)Report a problem with this question
51. According to the Arrhenius definition, what characterizes an acid in aqueous solution?
- A.It increases the concentration of hydrogen ions (H+)✓ Answer
- B.It increases the concentration of hydroxide ions (OH-)
- C.It always has a pH greater than 7
- D.It feels slippery and tastes bitter
By the Arrhenius definition, an acid dissociates in water to increase the hydrogen ion (H+) concentration, which lowers pH below 7; increasing hydroxide ions and a slippery, bitter feel describe bases instead.
Source: ATI TEAS 7 Science outline — Chemistry: acids and bases (Arrhenius definition)Report a problem with this question
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