Comprehensive Final Examination

1. [Safety] A planned investigation has a serious risk that cannot be controlled with available equipment. What should happen first?

1. Revise or replace the method before beginning.
2. Proceed with fewer trials.
3. Ask participants to accept the risk.
4. Continue if the scientific question is important.

2. [Personal protection] Which action is appropriate when an approved activity requires splash goggles?

1. Share one pair while materials are being handled.
2. Wear correctly fitting splash goggles for the entire exposure period.
3. Wear ordinary eyeglasses instead.
4. Remove the goggles whenever they fog.

3. [Chemical habits] What is the safest rule for an unlabeled substance?

1. Taste a tiny amount.
2. Mix it with water to see what happens.
3. Do not handle or use it; inform the supervising adult.
4. Smell it closely to identify it.

4. [Emergency response] A liquid splashes into a student’s eye during a supervised laboratory activity. What is the correct immediate response?

1. Finish recording data before responding.
2. Rub the eye with a dry towel.
3. Wait to see whether pain develops.
4. Use the approved eyewash procedure immediately and alert the supervisor.

5. [Data integrity] A result does not match the other trials. What is the most responsible response?

1. Document it, check the method and equipment, and repeat if appropriate.
2. Delete it without explanation.
3. Change it to equal the mean.
4. Conclude that all other trials are wrong.

6. [Ethics] Which study plan requires informed consent and additional ethical safeguards?

1. Timing a paper helicopter.
2. Collecting identifiable health information from human participants.
3. Measuring the length of classroom pencils.
4. Using a published anonymous dataset.

7. [Environmental responsibility] Which field practice is appropriate?

1. Remove rare specimens for a personal collection.
2. Publish exact locations of vulnerable species.
3. Observe from a permitted stable location and minimize disturbance.
4. Enter a protected nesting area for a closer photograph.

8. [Scientific habits] Which notebook entry best supports reproducibility?

1. Only the final conclusion.
2. A copied procedure with no changes recorded.
3. A list of results without units.
4. Date, materials, exact method, measurements, changes, and unexpected events.

9. [Variables] A student changes light intensity and measures the oxygen production rate of an aquatic plant. What is the independent variable?

1. Light intensity.
2. Oxygen production rate.
3. Plant species.
4. Elapsed measurement time.

10. [Measurement] Repeated measurements are 12.2 cm, 12.2 cm, 12.3 cm, and 12.2 cm. What can be concluded from these values alone?

1. There is no measurement uncertainty.
2. The measurements are precise.
3. The measurements are accurate.
4. The true value is 12.225 cm.

11. [Data processing] What is the mean of 4.0, 4.5, 5.0, and 4.5 seconds?

1. 4.75 seconds.
2. 18.0 seconds.
3. 4.5 seconds.
4. 4.0 seconds.

12. [Graphs] Which graph is generally most suitable for showing the relationship between temperature and reaction rate?

1. A pie chart.
2. A pictogram.
3. A single-category bar chart.
4. A scatter plot or line graph with two numerical axes.

13. [Reliability] Why are repeated trials useful?

1. They reveal variation and improve confidence in an estimate such as the mean.
2. They prove the hypothesis.
3. They remove all random error.
4. They guarantee accuracy.

14. [Causation] An observational study finds an association between screen time and sleep duration. Which conclusion is justified?

1. No confounding variable could exist.
2. The variables were associated in the observed sample, but causation is not established.
3. Screen time caused every sleep difference.
4. Sleep duration caused all screen use.

15. [Claim-evidence-reasoning] Which statement is scientific reasoning rather than a claim or a measurement?

1. The reaction lasted 24 seconds.
2. Three trials were completed.
3. Greater surface area increases collision opportunities, explaining the faster measured reaction.
4. The powdered sample reacted faster.

16. [Uncertainty] A ruler has millimetre markings. Which report best reflects its resolution for a direct length reading?

1. Report twenty decimal places.
2. Report no units.
3. Claim the length is exact.
4. Report to the nearest millimetre and acknowledge reading uncertainty.

17. [Cell theory] Which statement is part of modern cell theory?

1. All living organisms consist of one or more cells.
2. Every cell has a nucleus.
3. Viruses are complete cells.
4. Cells arise only from nonliving matter.

18. [Cell structures] Which structures occur in all known cells?

1. A Golgi apparatus and lysosomes.
2. A plasma membrane and ribosomes.
3. A nucleus and mitochondria.
4. Chloroplasts and a cell wall.

19. [Classification] Which feature distinguishes a typical eukaryotic cell from a typical prokaryotic cell?

1. It has a plasma membrane.
2. It contains genetic material.
3. Most DNA is enclosed in a membrane-bound nucleus.
4. It has ribosomes.

20. [Microscopy] A specimen is 0.04 mm long and its image is 20 mm long. What is the magnification?

1. 50×.
2. 800×.
3. 0.002×.
4. 500×.

21. [Transport] Osmosis is the net movement of:

1. Water across a selectively permeable membrane from higher water potential toward lower water potential.
2. Solute from low concentration to high concentration without energy.
3. All particles through any membrane.
4. Water only from low solute concentration to low solute concentration.

22. [Surface area] Why does a high surface-area-to-volume ratio support exchange?

1. It prevents all water movement.
2. More membrane area is available relative to the material requiring exchange.
3. It eliminates diffusion distance.
4. It creates energy.

23. [Energy and matter] Which statement correctly links photosynthesis and cellular respiration?

1. Respiration occurs only in animals.
2. Photosynthesis destroys carbon atoms.
3. Photosynthesis stores energy in organic molecules, while respiration transfers usable energy from those molecules.
4. Both processes require sunlight at every step.

24. [Organization] Which sequence is ordered from smaller to larger biological organization?

1. Organ → cell → tissue → organism.
2. Tissue → organ system → cell → organ.
3. Organ system → organ → tissue → cell.
4. Cell → tissue → organ → organ system.

25. [Homeostasis] Homeostasis is best described as:

1. Dynamic regulation of internal conditions within functional ranges.
2. Keeping every variable perfectly constant.
3. A process occurring only during illness.
4. The absence of environmental change.

26. [Feedback] Which sequence represents a negative-feedback system?

1. Stimulus → random action with no information pathway.
2. Change → receptor → coordinating centre → effector → response that reduces the change.
3. Change → amplifier → response that increases the change indefinitely.
4. Effector → receptor → no response.

27. [Circulation] What is the primary role of red blood cells?

1. Filter urine.
2. Transmit nerve impulses.
3. Transport oxygen using haemoglobin.
4. Produce digestive enzymes.

28. [Gas exchange] Which adaptation increases gas-exchange efficiency in alveoli?

1. Thick dry walls.
2. Low blood supply.
3. A small number of sealed chambers.
4. Large surface area and a thin exchange barrier.

29. [Digestion] Most absorption of digested nutrients occurs in the:

1. Small intestine.
2. Stomach.
3. Large intestine.
4. Oesophagus.

30. [Excretion] The kidneys help regulate:

1. Only food intake.
2. Water, ions, pH, and removal of nitrogenous wastes.
3. Only body temperature.
4. Only oxygen uptake.

31. [Coordination] Compared with endocrine signalling, nervous signalling is generally:

1. Carried only in blood.
2. Unable to affect muscles.
3. Faster and more targeted.
4. Always slower and more widespread.

32. [Health data ethics] A classroom heart-rate record should be used to:

1. Diagnose heart disease.
2. Publish named student records.
3. Replace professional medical evaluation.
4. Explore physiological patterns without diagnosing a medical condition.

33. [Genetic organization] Which sequence is correct?

1. DNA contains genes and is organized into chromosomes.
2. Chromosomes contain cells inside genes.
3. Genes contain organisms.
4. Alleles are made of tissues.

34. [Mitosis] Mitosis usually produces:

1. Gametes only.
2. Two genetically similar daughter cells with the same chromosome number as the parent cell.
3. Four genetically varied haploid cells.
4. One cell with twice the chromosome number.

35. [Meiosis] Meiosis contributes to variation through:

1. Preventing chromosome separation.
2. Eliminating all mutation.
3. Crossing over, independent assortment, and random fertilization.
4. Producing identical diploid cells.

36. [Probability] For Aa × Aa, what is the expected probability of genotype aa?

1. 1/2.
2. 3/4.
3. 1.
4. 1/4.

37. [Phenotype] Phenotype is influenced by:

1. Genotype and environmental conditions.
2. Genotype only in every trait.
3. Environment only in every trait.
4. Neither inheritance nor environment.

38. [Mutation] A mutation is:

1. A change in exercise level.
2. A change in genetic material that may be neutral, harmful, or beneficial depending on context.
3. Always harmful.
4. Always inherited by offspring.

39. [Cell cycle] Why is cell-cycle regulation important?

1. It stops all cell replacement.
2. It produces gametes by mitosis.
3. It coordinates division and helps limit uncontrolled proliferation.
4. It guarantees that cancer cannot occur.

40. [Genetic ethics] Which principle is essential when using identifiable genetic information?

1. Public release without permission.
2. Treating probability as destiny.
3. Using ancestry claims to rank human worth.
4. Consent, privacy, limited access, and recognition of uncertainty.

41. [Ecological organization] Which term describes all populations of different species living and interacting in an area?

1. Community.
2. Population.
3. Habitat.
4. Organism.

42. [Energy flow] Why is less energy available at higher trophic levels?

1. Matter stops cycling.
2. Organisms use and dissipate much energy through metabolism and heat transfer.
3. Energy atoms are destroyed.
4. Predators cannot digest food.

43. [Population ecology] A population exceeds resource availability and then declines. Which factor most directly explains the decline?

1. Creation of new energy.
2. Removal of all variation.
3. Density-dependent limitation such as competition for food.
4. Unlimited carrying capacity.

44. [Biodiversity] Species richness measures:

1. The total biomass only.
2. The genetic sequence of one organism.
3. The age of an ecosystem.
4. The number of species present.

45. [Natural selection] Natural selection requires:

1. Heritable variation and differences in reproductive success.
2. Individuals changing genes because they need to.
3. All organisms surviving equally.
4. No environmental influence.

46. [Evidence for evolution] Which is direct empirical evidence used to reconstruct evolutionary relationships?

1. The assumption that all similarities have one cause.
2. DNA sequence similarities and differences.
3. A philosophical preference.
4. A single unsupported story.

47. [Ecosystem resilience] An ecosystem is generally more resilient when it has:

1. No disturbance history.
2. No nutrient cycling.
3. Functional diversity and multiple pathways that can maintain processes.
4. Only one species performing each function.

48. [Conservation] Which plan is strongest?

1. Move organisms without permits.
2. Publish sensitive nest locations.
3. Choose an action without baseline data.
4. Protect habitat, involve affected communities, monitor outcomes, and revise using evidence.

49. [Atomic identity] The atomic number equals the number of:

1. Protons.
2. Neutrons plus electrons.
3. Neutrons only.
4. Electron shells.

50. [Particle counts] A neutral atom has atomic number 12. How many electrons does it have?

1. 10.
2. 12.
3. 6.
4. 24.

51. [Isotopes] Isotopes of the same element differ in their number of:

1. Valence shells only.
2. Nuclei.
3. Neutrons.
4. Protons.

52. [Ions] An atom with 17 protons and 18 electrons has charge:

1. +1.
2. 0.
3. −17.
4. −1.

53. [Relative atomic mass] Why is a periodic-table atomic mass often not a whole number?

1. It is an abundance-weighted average of naturally occurring isotopes.
2. Atoms contain fractional protons.
3. Every isotope has the same abundance.
4. Electrons have no mass.

54. [Electron arrangement] For elements 1–20, group patterns are strongly related to:

1. The number of compounds already discovered.
2. Outer-electron arrangements.
3. Neutron color.
4. Nuclear size only.

55. [Periodic trends] Which broad statement is accurate?

1. Halogens are metals.
2. All elements in a period have identical properties.
3. Group 1 metals generally become more reactive down the group.
4. Noble gases are highly reactive.

56. [Atomic models] Why have atomic models changed over time?

1. Atoms changed their laws.
2. Scientists preferred more complex drawings.
3. No experiments were involved.
4. New evidence required revision of earlier explanations.

57. [Ionic bonding] Ionic bonding is the electrostatic attraction between:

1. Oppositely charged ions.
2. Neutral molecules only.
3. Two nuclei with no electrons.
4. Identical atoms sharing no particles.

58. [Covalent bonding] A covalent bond involves:

1. Destruction of valence electrons.
2. A shared pair of electrons between atoms.
3. A neutron transfer.
4. Only attraction between separate ions.

59. [Formulae] What is the neutral formula formed from Mg²⁺ and Cl⁻?

1. MgCl.
2. Mg₂Cl₂.
3. MgCl₂.
4. Mg₂Cl.

60. [Conservation] Why must a chemical equation be balanced?

1. Molecules must have equal masses individually.
2. Energy is never transferred.
3. Coefficients change element identities.
4. Atoms are rearranged but conserved in a closed chemical reaction.

61. [Reaction energy] In an exothermic reaction:

1. The system transfers net energy to the surroundings.
2. The surroundings transfer net energy into the system.
3. No bonds change.
4. Temperature must always remain constant.

62. [Reaction rate] Why does increasing temperature often increase reaction rate?

1. Products disappear.
2. Particles collide more frequently and a larger fraction have sufficient energy.
3. Atoms become larger.
4. Catalysts are automatically created.

63. [Catalysts] A catalyst increases reaction rate by:

1. Being consumed as the main reactant.
2. Raising atomic number.
3. Providing an alternative pathway with lower activation energy.
4. Increasing the equilibrium amount of every product.

64. [Equilibrium] Dynamic equilibrium in a closed system means:

1. All reactions stop.
2. Reactant and product concentrations must be equal.
3. The container contains only products.
4. Forward and reverse reactions continue at equal rates.

65. [Motion] A runner moves 100 m east in 20 s. Average velocity is:

1. 5.0 m/s east.
2. 5.0 m/s west.
3. 2000 m/s.
4. 0 m/s.

66. [Acceleration] Velocity changes from 4 m/s to 10 m/s in 3 s. Average acceleration is:

1. 30 m/s².
2. 2 m/s².
3. 6 m/s².
4. 14 m/s².

67. [Graphs] The slope of a position–time graph represents:

1. Force.
2. Momentum.
3. Velocity.
4. Acceleration directly.

68. [Net force] A 20 N force acts right and an 8 N force acts left. Net force is:

1. 28 N right.
2. 12 N left.
3. 160 N right.
4. 12 N right.

69. [Newton’s second law] A 4 kg object experiences a 12 N net force. Its acceleration is:

1. 3 m/s².
2. 48 m/s².
3. 0.33 m/s².
4. 16 m/s².

70. [Momentum] A 2 kg cart moves at 5 m/s. Momentum is:

1. 25 kg·m/s.
2. 10 kg·m/s.
3. 2.5 kg·m/s.
4. 7 kg·m/s.

71. [Energy] A 3 kg object moves at 4 m/s. Kinetic energy is:

1. 12 J.
2. 48 J.
3. 24 J.
4. 6 J.

72. [Power and efficiency] A device transfers 600 J in 20 s. Its average power is:

1. 12 W.
2. 120 W.
3. 12,000 W.
4. 30 W.

73. [Electricity] Current is defined as:

1. Charge transferred per unit time.
2. Energy per unit charge.
3. Resistance multiplied by time.
4. Power divided by voltage only.

74. [Ohm’s law] A 12 V potential difference is across a 6 Ω resistor. Current is:

1. 72 A.
2. 2 A.
3. 0.5 A.
4. 6 A.

75. [Parallel circuits] In a parallel circuit, each branch has:

1. Zero resistance.
2. No energy transfer.
3. The same potential difference as the source, under the ideal model.
4. The same current in every branch regardless of resistance.

76. [Power] A device operates at 9 V and 0.50 A. Electrical power is:

1. 18 W.
2. 0.056 W.
3. 9.5 W.
4. 4.5 W.

77. [Magnetism] Electromagnetic induction requires:

1. A change in magnetic flux through a circuit.
2. A constant unchanging magnetic field only.
3. No conductor.
4. Chemical combustion.

78. [Waves] A wave has frequency 5 Hz and wavelength 3 m. Wave speed is:

1. 0.6 m/s.
2. 15 m/s.
3. 1.67 m/s.
4. 8 m/s.

79. [Refraction] When a wave enters a slower medium, its frequency generally:

1. Always doubles.
2. Changes independently of the source.
3. Remains set by the source while speed and wavelength change.
4. Becomes zero.

80. [Digital information] Why can digital systems often regenerate a noisy signal?

1. Digital data contain no noise.
2. Every error is automatically corrected.
3. Sampling has no limits.
4. Receivers can classify values into discrete states and reconstruct them within tolerance.

81. [Earth systems] A flux is:

1. A rate of transfer between reservoirs.
2. A stored amount only.
3. A rock type.
4. A fixed system boundary.

82. [Earth interior] Which evidence supports a liquid outer core?

1. Cloud formation.
2. S waves do not propagate through part of Earth’s interior.
3. Ocean tides.
4. Surface soil colour.

83. [Plate tectonics] A mid-ocean ridge is associated with:

1. Continental collision.
2. No plate motion.
3. A divergent plate boundary.
4. A transform boundary only.

84. [Surface processes] Weathering differs from erosion because weathering:

1. Always transports sediment.
2. Occurs only in rivers.
3. Requires melting.
4. Breaks material down in place.

85. [Water budget] Precipitation is 100 mm, evapotranspiration 35 mm, and runoff 45 mm. Storage change is:

1. 20 mm.
2. 10 mm.
3. 80 mm.
4. 180 mm.

86. [Carbon cycle] A reservoir receives 60 units/year and loses 45 units/year. Net change is:

1. 105 units/year.
2. +15 units/year.
3. −15 units/year.
4. 0 units/year.

87. [Nutrient cycles] Why can excess nutrient input lower dissolved oxygen in water?

1. Water stops moving permanently.
2. Nitrogen becomes radioactive.
3. Increased production and decomposition can increase oxygen consumption.
4. Nutrients destroy oxygen atoms.

88. [Climate energy] Incoming solar energy is 340 W/m² and albedo is 0.30. Absorbed solar energy is:

1. 102 W/m².
2. 340 W/m².
3. 442 W/m².
4. 238 W/m².

89. [Seasons] Earth’s seasons are caused primarily by:

1. Axial tilt changing solar angle and day length.
2. Large changes in Earth–Sun distance.
3. The Moon’s shadow.
4. Changes in the Sun’s mass.

90. [Lunar phases] Ordinary lunar phases result from:

1. Clouds in Earth’s atmosphere.
2. Changing viewing geometry of the Moon’s sunlit half.
3. Earth’s shadow covering the Moon every month.
4. The Moon changing its own light output.

91. [Light-time] Light travels 3.0×10⁸ m/s. Time to travel 1.5×10¹¹ m is:

1. 5000 s.
2. 4.5×10¹⁹ s.
3. 500 s.
4. 50 s.

92. [Orbits] In a circular orbit, velocity is approximately tangent to the path while acceleration points:

1. Along the velocity.
2. Away from the central body.
3. Nowhere.
4. Toward the central body.

93. [Spectra] A spectral line shifts from 600 nm to 603 nm. Redshift z is:

1. 0.005.
2. 0.0005.
3. 0.05.
4. 1.005.

94. [Stellar evolution] Compared with low-mass stars, high-mass stars generally:

1. Remain protostars.
2. Use fuel faster and have shorter lifetimes.
3. Live longer because they contain more fuel.
4. Never undergo fusion.

95. [Exoplanets] A transit depth of 1% gives an approximate planet-to-star radius ratio of:

1. 0.50.
2. 1.00.
3. 0.10.
4. 0.01.

96. [Cosmology] Which combination supports an evolving hot early universe?

1. Seasons, tides, and weather.
2. Only one galaxy image.
3. A single solar flare.
4. Galaxy redshift trends, cosmic microwave background radiation, and primordial light-element abundances.

97. [Problem definition] A strong engineering need statement should identify:

1. The affected users, context, measurable need, and important boundaries.
2. A preferred solution before research.
3. Only the designer’s opinion.
4. No stakeholders.

98. [Criteria and constraints] Which is a constraint?

1. The team likes recycled material.
2. The design must not exceed the approved cost and safety limits.
3. The design should be visually attractive.
4. The design should maximize user preference.

99. [Decision matrices] Why should criterion weights be established before scoring concepts?

1. To remove the need for evidence.
2. To make all criteria equal.
3. To reduce manipulation of priorities after seeing preferred results.
4. To guarantee the highest score is safe.

100. [Testing] Why are repeated prototype trials important?

1. They guarantee the design is optimal.
2. They eliminate measurement uncertainty.
3. They replace a baseline.
4. They reveal variability and support estimates of reliability.

101. [Life cycle] A life-cycle comparison should use:

1. The same functional unit and system boundary for all options.
2. Different service levels for each concept.
3. Only manufacturing impacts.
4. Only end-of-life impacts.

102. [Risk] A high weighted score cannot justify a concept that:

1. Requires one additional calculation.
2. Fails a hard safety or legal constraint.
3. Has a lower aesthetic score.
4. Uses a different colour.

103. [Reliability] For required independent components in series, overall reliability is:

1. Always equal to the most reliable component.
2. Unrelated to component performance.
3. The product of the component reliabilities.
4. The sum of the reliabilities.

104. [Iteration] Evidence-based iteration means:

1. Changing success criteria to make the design pass.
2. Hiding unsuccessful trials.
3. Selecting the first concept permanently.
4. Revising the design in response to test evidence while documenting changes and tradeoffs.