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Scientific Method MCQs for MDCAT Practice

Science Reasoning section, Scientific Method chapter. Up to eight free sample questions, each with the correct answer and a worked explanation. The full chapter opens in the app.

The bank has 26 active questions on this chapter. Your first 500 practice attempts are free, and every attempt includes a worked explanation.

  1. Question 1
    Blue green algae and bacteria belong to kingdom
    • Animalia
    • Monera (correct answer)
    • Protista
    • Protozoa
    Correct answer: B
    Blue-green algae (cyanobacteria) are prokaryotes, placing them in Kingdom Monera, not in eukaryotic kingdoms like Animalia, Protista, or the outdated Protozoa.
  2. Question 2
    Battery companies make impressive claims about how long their batteries will last. A student decided to test the running time of different batteries to determine which battery lasts the longest. The student tested 6 different batteries, 4 brand name and 2 generic, using flashlights. The results show that the battery referred to as Name Brand A lasted the longest, with 101 hours of runtime: It could be argued that this experiment was not set up using proper experimental protocol. What would need to change in the experiment for the results to be valid?
    • The batteries should have all been either name brand or generic
    • Only two groups should have been tested at a time
    • The same battery should have been used in each flashlight
    • The same flashlight should have been used to test each battery (correct answer)
    Correct answer: D
    To ensure valid battery testing, a consistent experimental setup is crucial. Using the same flashlight for all batteries controls for variations in flashlight performance, isolating battery type as the sole variable.
  3. Question 3
    Which is the correct sequence of the scientific method?
    • Observation → Theory → Experiment → Hypothesis
    • Theory → Experiment → Observation → Hypothesis
    • Observation → Hypothesis → Experiment → Conclusion (correct answer)
    • Hypothesis → Observation → Theory → Law
    Correct answer: C
    Master the scientific method's logical flow, from initial observation to drawing conclusions, to correctly interpret experimental design and outcomes.
  4. Question 4
    An experimenter is attempting to determine the effects of smoking on VLBW (Very Low Birth Weight) and of VLBW on IQ. Which of the following statements are correct? I. Smoking is an independent variable. II. Smoking is a dependent variable. III. VLBW is an independent variable. IV. VLBW is a dependent variable.
    • I and IV only.
    • II and IV only.
    • I, III, and IV only. (correct answer)
    • II, III, and IV only.
    Correct answer: C
    Understand independent vs. dependent variables in experimental design to analyze the relationship between smoking, VLBW, and IQ.
  5. Question 5
    A scientist tests a drug on 100 patients, but there is no control group. What is the most significant flaw?
    • The sample size is too small
    • The drug may have side effects
    • There's no basis for comparison (correct answer)
    • The patients might not have followed instructions
    Correct answer: C
    A study without a control group lacks a baseline for comparison, making it impossible to attribute observed effects solely to the intervention.
  6. Question 6
    Order the following steps to separate a mixture of sodium chloride, sand, and iron.I- Mix in waterII- EvaporateIII- hold a magnet bar above the mixture/solutionIV- Filter and dry filtrate
    • I → II → III → IV
    • II → III → IV → I
    • I → III → IV → II
    • III → I → IV → II (correct answer)
    Correct answer: D
    Separate a mixture of iron, sand, and salt using physical methods based on differing physical properties: magnetism, solubility, and boiling point.
  7. Question 7
    Change the narration:He said, "Are you interested in my book?"
    • He told me if I was interested in his work
    • He asked to me that I was interested in my work
    • He asked if I was interested in his book (correct answer)
    • He asked if he was interested in my work
    Correct answer: C
    Direct speech with a question containing 'my' must be changed to indirect speech using 'asked if' and possessive pronoun 'his' with correct verb tense.
  8. Question 8
    What is the best method to test if a gas is oxygen?
    • Bubble it through limewater
    • Bring a glowing splint near it (correct answer)
    • Smell it
    • See if it dissolves in water
    Correct answer: B
    A glowing splint test, which relights in the presence of oxygen, is the definitive method for identifying this vital gas.

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Read the full Scientific Method chapter notes: Scientific Method notes. Or browse every chapter.