Hypothesis and Inference MCQs for MDCAT Practice

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

1. Question 1
   “The World Health Organization has recorded 184 human cases of the H5N1 strain of bird flu, all of them caused by contact with infected birds. That 103 of these have resulted in death indicates how dangerous this virus is, and no vaccine has yet been developed. For there to be a worldwide epidemic of H5N1 amongst humans, it would have to be possible for the virus to be passed easily from one person to another. Unlike normal influenza, H5N1 can only bind to receptors deep in the lungs. As a result, it cannot multiply in the upper respiratory system and thereby be transmitted by sneezing and coughing. So it cannot be transmitted easily between people. Influenza viruses can mutate and thus possibly change the way in which they infect victims.” Which of the following can be drawn as a conclusion from the passage above?
   • AUnless a vaccine is developed, many more people will catch the H5N1 strain of bird flu.
   • BIf H5N1 mutates, there is likely to be a worldwide epidemic amongst humans of this strain of bird flu.
   • CUnless H5N1 mutates, a worldwide epidemic amongst humans of this strain of bird flu is unlikely. (correct answer)
   • DIf a person has no contact with birds, they are unlikely ever to catch the H5N1 strain of bird flu.
   Correct answer: C

   The passage implies H5N1's limited human-to-human transmission is due to its lung-specific binding, suggesting mutation is key for a pandemic.
2. Question 2
   Blood is composed of cells (corpuscles) and a liquid intercellular ground substance called Plasma.The type of the blood group that a person has depends upon the presence or absence of certain specific substances in the red blood cells. These substances are antigens, and are of two kinds, Antigen A and Antigen B.A person with antigen A has a blood group A, and one with antigen B has blood group B. A person with A and B antigens has blood group AB. Similarly a person lacking both antigens falls in blood group O.phenotypic and genotypic characteristics may be expressed as follows;Two people are planning to have a family. The woman has blood genotype A/A and the man B/B. Their children might have:
   • AA and B
   • BA/B only (correct answer)
   • CB only
   • DA and B and A/B
   Correct answer: B

   Determine child's blood group based on parental genotypes A/A and B/B, illustrating Mendelian inheritance of ABO blood groups.
3. Question 3
   The dogs ______ escaped.
   • ADid
   • BHas
   • CHad (correct answer)
   • DWill
   Correct answer: C

   This question tests the correct auxiliary verb to form the past perfect tense with a plural subject.
4. Question 4
   The living room of my house contains a mirror which is positioned so that I can see a reflection of the digital clock when I am standing in the hallway. For example, at 12:15 I can see the following: 21:51I have to be careful, because if I forget that it is a reflection I might think that it is 21:51.On the next occasion that the mirror appears to show a real time, what time will be shown in the mirror?
   • A05:51
   • B12:20
   • C15:51 (correct answer)
   • D21:52
   Correct answer: C

   Decode reflected digital clock times by applying a reflection transformation to determine the next visible real time.
5. Question 5
   “The World Health Organisation has recorded 184 human cases of the H5N1 strain of bird flu, all of them caused by contact with infected birds. That 103 of these have resulted in death indicates how dangerous this virus is, and no vaccine has yet been developed. For there to be a worldwide epidemic of H5N1 amongst humans, it would have to be possible for the virus to be passed easily from one person to another. Unlike normal influenza, H5N1 can only bind to receptors deep in the lungs. As a result, it cannot multiply in the upper respiratory system and thereby be transmitted by sneezing and coughing. So it cannot be transmitted easily between people. Influenza viruses can mutate, and thus possibly change the way in which they infect victims.” Which of the following can be drawn as a conclusion from the passage above?
   • AUnless a vaccine is developed, many more people will catch the H5N1 strain of bird flu.
   • BIf H5N1 mutates, there is likely to be a worldwide epidemic amongst humans of this strain of bird flu. (correct answer)
   • CUnless H5N1 mutates, a worldwide epidemic amongst humans of this strain of bird flu is unlikely.
   • DIf a person has no contact with birds, they are unlikely ever to catch the H5N1 strain of bird flu.
   Correct answer: B

   H5N1's current transmission limits human-to-human spread, but mutation could enable a pandemic.
6. Question 6
   Experiment: To study reflex action, a subject’s knee-jerk response was tested after applying pressure to the thigh nerve.Observation: The reflex was immediate and involuntary.Question: Which conclusion is accurate?
   • AAll voluntary actions require reflexes.
   • BReflex arcs begin in the brain.
   • CReflexes are fast, involuntary responses bypassing the brain. (correct answer)
   • DPressure slows down reflexes.
   Correct answer: C

   The knee-jerk reflex is immediate & involuntary, demonstrating that reflexes bypass conscious brain processing for speed.
7. Question 7
   Gases consist of molecules which are in a state of rapid motion. The fact that the molecules are in motion is evident from the fact that if a small quantity of an odorous gas, such as hydrogen sulphide is liberated at any point in a laboratory the smell of the gas soon pervades the whole room.Suppose a balloon has been filled with an unknown odorless gas. Having no sophisticated equipment at hand, it is decided to bubble the gas through calcium hydroxideIf a precipitate forms the gas is identified as:
   • Asulphur dioxide
   • Bcarbon dioxide (correct answer)
   • Ccarbon monoxide
   • Dammonia
   Correct answer: B

   Detecting CO2 gas by observing precipitate formation when bubbled through calcium hydroxide, a common qualitative analysis test.
8. Question 8
   A dice is numbered from 1 to 6 in different ways. If 1 is adjacent to 2, 4, and 6, then which of the following statements is necessarily true?
   • A2 is opposite to 6
   • B1 is adjacent to 3
   • C3 is adjacent to 5 (correct answer)
   • D3 is opposite to 5
   Correct answer: C

   Deduce the arrangement of numbers on a dice based on adjacency rules. This tests spatial reasoning and logical deduction.

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