SCSA Biology Science Inquiry Skills
15 sample questions with marking guides and sample answers · Avg. score: 66.5%
A bacterial pathogen causes eye disease in finches. Biologists wanted to know whether the finches could evolve resistance to this pathogen. Finches from a population that had prior exposure to the pathogen, and from a population that had no prior exposure, were infected with the pathogen deliberately. After two weeks, the biologists determined the pathogen load in the two groups of finches. The independent variable in this experiment is the
deliberate infection of finches with the pathogen.
prior exposure of a population to the pathogen.
two-week duration of the experiment.
pathogen load in the two groups of finches.
Reveal Answer
deliberate infection of finches with the pathogen.
Deliberate infection is a procedure applied equally to all finches in the experiment, not a variable being manipulated or compared between groups.
prior exposure of a population to the pathogen.
The independent variable is the condition that differs between the groups being compared, which in this case is whether the finch population had prior exposure to the pathogen.
two-week duration of the experiment.
The two-week duration is a controlled variable kept constant for all finches, not the independent variable being tested.
pathogen load in the two groups of finches.
The pathogen load is the dependent variable, as it is the outcome being measured to see the effect of the independent variable.
The purpose of a 'control' in an experiment is to
determine the reliability of the experiment.
provide a comparison for the experimental treatment.
reduce the sample sizes needed for the experiment to be valid.
minimise the number of variables to be tested.
Reveal Answer
determine the reliability of the experiment.
Reliability is determined by repeating the experiment multiple times to check for consistent results, rather than by using a control group.
provide a comparison for the experimental treatment.
A control group provides a baseline where the independent variable is not applied, allowing researchers to see the actual effect of the experimental treatment by comparison.
reduce the sample sizes needed for the experiment to be valid.
Using a control group does not reduce the required sample size; in fact, larger sample sizes generally increase the statistical power and validity of an experiment.
minimise the number of variables to be tested.
While researchers keep certain variables constant to isolate the independent variable, the control group itself serves as a baseline for comparison, not a tool to reduce the number of variables.
A student designed and conducted a practical investigation to test for the presence of microbes in water and food samples.
Justify a safety precaution required to prevent infection when conducting the investigation.
Reveal Answer
The wearing of gloves to prevent contact with skin and the subsequent entry of pathogens into skin/mouth
| Descriptor | Marks |
|---|---|
Justifies a safety precaution used to prevent infection | 2 |
Provides some relevant information | 1 |
None of the above | 0 |
Explain how the student could ensure the reliability of the investigation.
Reveal Answer
The student could repeat the experiment by using five plates to culture the same sample of food or water. This would mean the student could check that the results are similar in each test.
| Descriptor | Marks |
|---|---|
Explains how to ensure the investigation is reliable | 2 |
Provides some relevant information | 1 |
None of the above | 0 |
The table shows data from a transect study along a sand dune.
| Zone | ||||
|---|---|---|---|---|
| A | B | C | D | |
| Distance from sea (m) | 0–100 | >100–150 | >150–250 | >250–300 |
| Age of dune (years) | 0–50 | >50–100 | >100–125 | >125–150 |
| pH of soil | 8.4 | 7.4 | 6.9 | 6.0 |
| Organic matter in soil (%) | 1 | 2.5 | 5 | 30 |
| Number of grass species | 2 | 4 | 6 | 2 |
| Number of tree species | 0 | 1 | 3 | 8 |
Contrast species richness in zones A and D. Refer to data in your response.
Reveal Answer
Species richness is five times higher in zone D than zone A. Zone A has two different species, whereas zone D has 10.
| Descriptor | Marks |
|---|---|
Identifies species richness is higher in zone D | 1 |
Provides appropriate data | 1 |
Infer how organic matter affects the pH of soil. Justify your response.
Reveal Answer
As organic matter increased from 1% to 30%, the pH decreased from 8.4 to 6. This suggests that organic matter lowers soil pH.
| Descriptor | Marks |
|---|---|
Infers that organic matter lowers soil pH | 1 |
Justifies response using data | 1 |
Predict which zone would have the highest proportion of K-selected species. Explain your reasoning.
Reveal Answer
Zone D. Zone D is the oldest dune and has the highest species richness. This suggests it may be further along in succession. The number of K-selected species tends to increase as succession progresses.
| Descriptor | Marks |
|---|---|
Predicts zone D | 1 |
Provides appropriate reasoning | 1 |
A four-month investigation was undertaken in the classrooms of a large number of Year 2 and Year 3 students from four primary schools. For the first two months, half of the classes from each school used an antimicrobial gel hand sanitiser, while the other half used soap and water for regular hand hygiene. The students then switched hand-cleaning methods for the final two months. No significant differences in illness were observed between the groups.
The purpose of this investigation was most likely to
reduce water use in schools.
encourage students to wash their hands more often.
reduce the number of students who are away from school due to illness.
decide if purchasing antimicrobial gel hand sanitiser for students was worthwhile.
Reveal Answer
reduce water use in schools.
The investigation measured illness rates, not water consumption, so reducing water use was not the primary purpose of the study.
encourage students to wash their hands more often.
The study compared the effectiveness of two different hand-cleaning methods rather than trying to increase the overall frequency of handwashing.
reduce the number of students who are away from school due to illness.
Although reducing illness is a broad goal, the study specifically compared two methods to see if one was more effective, rather than just implementing a general illness reduction program.
decide if purchasing antimicrobial gel hand sanitiser for students was worthwhile.
By comparing the effectiveness of the sanitiser against standard soap and water in preventing illness, the schools could determine if the sanitiser offered enough benefit to justify its purchase.
Use the following information to answer the question.
Dengue is a disease primarily transported by mosquitoes. A group of students wish to investigate whether mosquitoes can be effectively controlled by spraying insecticide. The students will investigate the effect of spraying five different insecticides on mosquitoes.
Which one of the following techniques could the students use to generate quantitative primary data?
obtaining data from other students’ investigations
recording the smell of the five different insecticides
reading newspaper articles on the effect of insecticides on mosquitoes
measuring the mass of dead mosquitoes after spraying each insecticide
Reveal Answer
obtaining data from other students’ investigations
Obtaining data from other students' investigations is an example of collecting secondary data, not primary data.
recording the smell of the five different insecticides
Recording the smell of insecticides generates qualitative data (descriptive), not quantitative data (numerical).
reading newspaper articles on the effect of insecticides on mosquitoes
Reading newspaper articles is a method of gathering secondary data, as the information was collected and published by someone else.
measuring the mass of dead mosquitoes after spraying each insecticide
Measuring the mass of dead mosquitoes generates numerical (quantitative) data and is collected directly by the students conducting the experiment (primary data).
A student completed an experiment to investigate how light is reflected from different leaves. The results were recorded qualitatively.
Which one of the following could be a correct statement about the qualitative data obtained by the student?
An average result for the data could be obtained.
The same number would be recorded for each result.
The data was obtained by measuring the wavelength of light.
The data could be the names of the different colours of the reflected light.
Reveal Answer
An average result for the data could be obtained.
Qualitative data is descriptive and non-numerical, meaning it is not possible to calculate a mathematical average from it.
The same number would be recorded for each result.
Qualitative data consists of descriptions, characteristics, or categories, rather than numerical values.
The data was obtained by measuring the wavelength of light.
Measuring the wavelength of light produces numerical values with units, which is an example of quantitative data, not qualitative.
The data could be the names of the different colours of the reflected light.
Qualitative data describes qualities or characteristics. Recording the names of the colors of reflected light is a perfect example of qualitative data.
Three factors that affect the rate of photosynthesis in plants are stated below:
- Factor 1 – light intensity
- Factor 2 – carbon dioxide concentration
- Factor 3 – temperature
Scientific data consistently shows specific trends for each factor when other variables are controlled.
Graphs were plotted showing the rate of photosynthesis against an increasing change in each factor.
If plotted over a large range, which of the following would show graphs with the same trend?
factors 1 and 2
factors 1 and 3
factors 2 and 3
factors 1, 2 and 3
Reveal Answer
factors 1 and 2
Both light intensity and carbon dioxide concentration show the same trend: the rate of photosynthesis increases initially and then plateaus when another factor becomes limiting.
factors 1 and 3
Temperature shows a different trend than light intensity; it increases to an optimum point and then rapidly decreases as enzymes denature, whereas light intensity plateaus.
factors 2 and 3
Temperature increases to an optimum and then decreases due to enzyme denaturation, which is a different trend from carbon dioxide concentration, which simply plateaus.
factors 1, 2 and 3
Temperature has a distinct peak and decline curve due to enzyme denaturation, which differs from the plateauing curves of light intensity and carbon dioxide concentration.
Robert Koch produced a set of criteria to establish whether a particular organism is the cause of a disease in an animal. The criteria are listed below but not in the correct order.
- The microorganism must cause disease when introduced to a healthy experimental animal.
- The microorganism must be extracted and isolated from the diseased animal and subsequently grown in culture.
- The microorganism must be extracted from the diseased experimental animal and demonstrated to be the same microorganism that was isolated from the first diseased animal.
- The microorganism must be found in the diseased animal, and not found in healthy animals.
Which of the following correctly shows the order of steps required to determine the cause of a particular disease in an animal?
2, 3, 1, 4
2, 4, 1, 3
4, 2, 1, 3
4, 3, 2, 1
Reveal Answer
2, 3, 1, 4
This order incorrectly starts with isolating the microorganism before first establishing its presence in diseased animals and absence in healthy ones.
2, 4, 1, 3
This sequence is incorrect because it suggests isolating the microorganism before confirming it is exclusively found in diseased animals.
4, 2, 1, 3
This correctly follows Koch's postulates: first identify the pathogen in diseased animals (4), isolate and culture it (2), infect a healthy animal to cause disease (1), and finally reisolate it to confirm identity (3).
4, 3, 2, 1
This order is incorrect because it places the re-isolation of the microorganism from the experimental animal before actually infecting the healthy experimental animal.
Use the following information to answer the question.
Dengue is a disease primarily transported by mosquitoes. A group of students wish to investigate whether mosquitoes can be effectively controlled by spraying insecticide. The students will investigate the effect of spraying five different insecticides on mosquitoes.
The students want to check the reproducibility of their results.
To do this, they should ensure that the investigation
uses only recently calibrated equipment.
has both a positive and a negative control.
is conducted by only one student, in the same laboratory.
is conducted on different days by different students.
Reveal Answer
uses only recently calibrated equipment.
Using recently calibrated equipment improves the accuracy of the measurements, but it does not test whether the experimental results can be reproduced.
has both a positive and a negative control.
Controls are essential for the validity of an experiment to ensure the independent variable is causing the observed effect, but they do not check reproducibility.
is conducted by only one student, in the same laboratory.
Having the same student perform the experiment in the same lab tests repeatability (consistency under identical conditions), not reproducibility.
is conducted on different days by different students.
Reproducibility is the ability of an experiment to be duplicated by different researchers under different conditions (such as on different days) and still yield the same results.
Use the following information to answer the question.
Students investigated the proteins found in several different types of human cells.
Students completed their investigation and analysed their results. They suggested their results were affected by systematic errors.
Systematic errors
result in a spread of readings.
affect the precision of a measurement.
are easy to identify and eliminate.
cause readings to differ from the true value by a consistent amount each time.
Reveal Answer
result in a spread of readings.
Incorrect. Random errors cause a spread or scatter of readings, whereas systematic errors shift all measurements in the same direction.
affect the precision of a measurement.
Incorrect. Systematic errors affect the accuracy of a measurement, while random errors affect its precision.
are easy to identify and eliminate.
Incorrect. Systematic errors are often difficult to identify because the measurements may still appear highly precise despite being consistently inaccurate.
cause readings to differ from the true value by a consistent amount each time.
Correct. By definition, a systematic error consistently shifts all measurements by the same amount and in the same direction from the true value.
Use the following information to answer the question.
A Year 12 student conducts an investigation into the effects of different amounts of water on the growth of lettuce plants. The following table outlines some aspects of the investigation.
| Lettuce plant | Amount of water (mL/day) | Temperature (°C) | Light wavelength (nm) | Percentage increase in mass of lettuce (%) |
|---|---|---|---|---|
| 1 | 150 | 10 | 660 | 5 |
| 2 | 200 | 15 | 660 | 10 |
| 3 | 250 | 20 | 660 | 15 |
| 4 | 300 | 25 | 660 | 13 |
The investigation is not considered valid because
it contains more than one dependent variable.
only lettuce is used in the investigation.
the light wavelength is set at 660 nm.
the temperature is different for each plant.
Reveal Answer
it contains more than one dependent variable.
The investigation only has one dependent variable, which is the percentage increase in mass of the lettuce.
only lettuce is used in the investigation.
Using only one type of plant is necessary to control variables and ensure a fair test, so this does not invalidate the experiment.
the light wavelength is set at 660 nm.
Keeping the light wavelength constant at 660 nm is a controlled variable, which actually supports the validity of the experiment rather than undermining it.
the temperature is different for each plant.
For an experiment to be valid, only the independent variable (amount of water) should change. Because the temperature also changes, it acts as a confounding variable, making it impossible to know whether the water or the temperature caused the difference in growth.
Students designed a controlled experiment. After they had performed the experiment, another group of students gave them feedback suggesting that they should modify the experiment to improve the accuracy of their results.
A change that the first group of students could make to improve the accuracy of their results could include
ignoring outlying results.
repeating the experiment many times.
carefully calibrating the equipment used.
having many people take the measurements.
Reveal Answer
ignoring outlying results.
Ignoring outliers does not improve accuracy and can lead to biased results; outliers should be investigated to understand their cause rather than simply discarded.
repeating the experiment many times.
Repeating the experiment many times improves the reliability and precision of the results, but it does not correct systematic errors that affect accuracy.
carefully calibrating the equipment used.
Carefully calibrating equipment reduces systematic errors, ensuring that the measurements are as close to the true value as possible, which directly improves accuracy.
having many people take the measurements.
Having multiple people take measurements introduces human variability and potential error, which can decrease precision without improving accuracy.
Prior to modern human pregnancy test kits, Xenopus frogs were used. Urine samples from women were injected into the legs of female frogs. The frogs were then placed back into water tanks and, the following day, the tanks were checked for eggs. If a female frog had laid eggs, the woman who had provided the urine sample was diagnosed to be pregnant.
Which one of the following factors may result in a false diagnosis of pregnancy?
using male frogs instead of female frogs
maintaining an optimum tank temperature
replacing the water in the tanks with fresh water each day
female frogs laying eggs naturally around the time of the injection
Reveal Answer
using male frogs instead of female frogs
Male frogs cannot lay eggs, so using them would result in a false negative (no eggs laid), rather than a false positive diagnosis of pregnancy.
maintaining an optimum tank temperature
Maintaining an optimum temperature is a standard procedure to keep the frogs healthy and capable of responding to the hormone; it does not spontaneously induce egg-laying.
replacing the water in the tanks with fresh water each day
Replacing the water is a standard husbandry practice to maintain a clean environment and would not trigger spontaneous egg-laying.
female frogs laying eggs naturally around the time of the injection
If a frog lays eggs naturally, it would appear as a positive test result even if the woman's urine did not contain pregnancy hormones, leading to a false positive diagnosis.
A study assessed the effectiveness and safety of a drug called doxycycline. One hundred and fifty adults hospitalised with malaria were involved. These adults were randomly placed into two groups of equal size. One group received doxycycline in addition to standard care. The other group received standard care only.
The group receiving standard care only was the
control group.
variable group.
unsupported group.
experimental group.
Reveal Answer
control group.
The control group serves as a baseline for comparison by receiving the standard treatment without the new experimental drug.
variable group.
'Variable group' is not a standard scientific term; while variables are tested in an experiment, the groups are typically designated as control or experimental.
unsupported group.
'Unsupported group' is not a scientific term, and this group is still receiving standard medical care for their condition.
experimental group.
The experimental group is the one receiving the new intervention being tested, which in this study is the group receiving doxycycline.