ACT Science : How to find experimental design in biology
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Example Questions
Example Question #11 : How To Find Experimental Design In Biology
There is a certain species of rabbit that is known to reproduce quickly. 250 of these rabbits were introduced into a new environment, and their population was measured in ten year intervals.
What assumption did the scientists make in this experiment?
This species of rabbit will evolve to adapt to the new environment
There will be no external variables that may affect the population of the rabbits
This species of rabbit will reproduce at the same rate, regardless of environment
All brown rabbits reproduce at a faster rate than white rabbits
There will be no external variables that may affect the population of the rabbits
The scientists are attempting to isolate the rabbits and measure their population growth to discover some sort of rate of population increase. They are assuming that there will be no external forces acting upon the rabbits that might create fluctuations in population (disease, famine, predators, etc.)
The problem does not mention color, so that assumption is incorrect. The problem also does not compare reproductive rates in environments, so that assumption is incorrect. Finally, there is no mention of evolution or new traits, so that assumption is incorrect.
Example Question #11 : How To Find Experimental Design In Biology
There is a certain species of rabbit that is known to reproduce quickly. 250 of these rabbits were introduced into a new environment, and their population was measured in ten year intervals.
Which of the following statements, if true, might prevent the scientists from being able to generalize their findings to this species of rabbit as a whole?
250 rabbits is an ideal starting population from which to draw a reasonable conclusion
This species of rabbits has a natural fear of humans
No external or unforeseen variables acted upon the experiment
There was a genetic disorder found in this population of rabbits that caused them to have shorter life spans than the average rabbit of this species
There was a genetic disorder found in this population of rabbits that caused them to have shorter life spans than the average rabbit of this species
The experiment measures two things: time passed and population. If these rabbits have a disease that kills them faster than normal, this would affect population and population growth rate. The rate observed in the experiment would be lower than the rate of the general population.
Whether or not the species of rabbits has a natural fear of humans is irrelevant to the population/time passing equation. The other two answer choices, if true, would both support the findings.
Example Question #11 : How To Find Experimental Design In Biology
A spectrophotometer measures specific light wavelengths emitted by a sample. The readings of the samples are compared to those on a standard curve of known values. The standard curve creates a line and the equation of this line can be used to extrapolate the concentration of a given substance in samples whose spectrophotometric measurements fall within range of the curve.
A scientist is using this method to measure the amount of phosphorus within sediment samples. The phosphorus turns blue when reacted with a certain reagent. The scientist produces a valid standard curve; however, all of the samples surpass the curve's highest known value. Can the scientist use these samples and what should be done to rectify the situation.
No, the samples need to be recollected in smaller amounts in order to obtain valid results.
Yes, the scientist should assume that the samples are valid and utilize the curve anyway.
Yes, the samples need to be diluted to within range of the curve and then their values may be multiplied by the factor used for dilution.
No, the samples must be contaminated and need to be thrown out.
Yes, the samples need to be diluted to within range of the curve and then their values may be multiplied by the factor used for dilution.
Yes, the samples need to be diluted to within range of the curve and then their values may be multiplied by the factor used for dilution.
This is the correct approach. The scientist needs to dilute the samples by a factor of two. Then their concentrations may be multiplied by two. In doing so, the actual values are preserved. The samples should not be thrown out or re-collected. Furthermore, it is unreliable and unwise to utilize sample values outside a standard curve of known values as indicated in the passage.
Example Question #12 : How To Find Experimental Design In Biology
Chemical reactions involve two main components, reactants and products. The reactants, often referred to as substrates, interact with each other and rearrange in order to be converted into products. The speeds of these reactions are often defined by substrate concentration and the presence of enzymes. Enzymes are referred to as catalysts. Peroxidase is traditionally derived from turnips; however, it is commonly found in many plant and animal cells. This enzyme helps plant cells by removing hydrogen peroxide from cells in the form of tetraguaiacol.
Study 1
A scientist wants to observe the production of tetraguaiacol by observing a reaction between hydrogen peroxide and guaiacol. The product of this reaction is orange-brown in color. The scientist measures the intensity of color in each sample using a spectrophotometer. In the control experiment, the scientist mixed the substrates together and measured the reaction rate. In the test experiment, a peroxidase enzyme was added to a new set of substrates and rate of reaction was measured. The results of these reactions are plotted in Figure 1.
Figure 1
Study 2
A research team decides to study the effects of the peroxidase facilitated reaction in the presence of heat. Reaction rates are known to speed up when heat is applied; however, at a certain point enzymes, such as peroxidase, denature and the reaction slows. The scientists perform a control trial at room temperature 
Figure 2
What color does the spectrophotometer in Study 1 measure?
The brown color of guaiacol.
The orange-brown color of tetraguaiacol.
The clear color of hydrogen peroxide.
The orange-brown color of guaiacol.
The orange-brown color of tetraguaiacol.
The orange-brown color of tetraguaiacol.
The passage specifically states that tetraguaiacol has an orange-brown color. The products of the reation are water and tetraguaiacol. Water is clear in color and would not be read by the spectrophotometer. We do not know the color of guiacol or hydrogen peroxide; therefore, answers containing these substrates were incorrect.
Example Question #15 : How To Find Experimental Design In Biology
Criminal and deviant acts have plagued society for many years. Scientists have tried to isolate variables and factors of individuals susceptible to these behaviors. The goal of this research is to create models of individuals most likely to commit deviant acts. Prediction of criminal behavior could reduce crime rates on a grand scale. Three scientists express their views on how to model criminal behavior and predict or prevent criminal acts.
Scientist 1
Criminal behavior is the result of prehistoric tendencies that favor aggressive and deviant acts for survival. A study of the corpses of criminals revealed that many exhibited prominent brows, strong upper bodies, large chests and other attributes that lend to a physical model of prediction that classifies criminals as "evolutionary throwbacks."
Scientist 2
Criminal behavior is the result of psychological ills that may be remedied with treatment and hospitalization. Studies have revealed that many criminal men possess an XYY makeup. This means that they contain one extra Y chromosome that results in aggressive, deviant, and criminal behaviors. Further studies have revealed that these genetic abnormalities can alter hormonal secretion and lead to criminally deviant actions and behaviors. Increased serotonin levels can lead to aggressive tendencies while altered dopamine secretion can chemically reward the commitment of deviant acts by stimulating pleasure receptors.
Scientist 3
Criminal behavior is the result of neurological abnormalities that can be studied and mapped. Studies of criminal and non-criminal persons have revealed inconsistencies in brain scans and neurological makeup. These alterations in brain chemistry and function have resulted in the development of sociopathic and narcissistic tendencies. These tendencies often increase probabilities for deviant and violent outbursts. The best way to predict criminal behavior is to utilize neurological scanning and mapping procedures.
The passage states that Scientist 1 only studied the corpses of known criminals in order to develop his model. Is this method of research scientifically valid or reliable?
Yes, the subjects were criminals and their features therefore indicate criminal tendencies.
No, the researcher has no control group of non-criminal persons to compare with his data.
No, the researcher only observed physical attributes which may or may not relate to criminal behaviors.
Yes, the criminal subjects possessed striking physical likenesses to one another that must relate to their deviant behaviors.
No, the researcher has no control group of non-criminal persons to compare with his data.
No, the researcher has no control group of non-criminal persons to compare with his data.
This is the correct answer. The issue with this study relates to one of the most basic lessons in scientific investigation. In order to obtain reliable or valid results, one must have both a control and a test group. Even though Scientist 1, obtained compelling results there is no group of average non-criminal humans to compare it to. Every person on the planet could in someway possess these same traits and not be criminal. A case can be made for each of the other responses but none are correct.
Example Question #16 : How To Find Experimental Design In Biology
Criminal and deviant acts have plagued society for many years. Scientists have tried to isolate variables and factors of individuals susceptible to these behaviors. The goal of this research is to create models of individuals most likely to commit deviant acts. Prediction of criminal behavior could reduce crime rates on a grand scale. Three scientists express their views on how to model criminal behavior and predict or prevent criminal acts.
Scientist 1
Criminal behavior is the result of prehistoric tendencies that favor aggressive and deviant acts for survival. A study of the corpses of criminals revealed that many exhibited prominent brows, strong upper bodies, large chests and other attributes that lend to a physical model of prediction that classifies criminals as "evolutionary throwbacks."
Scientist 2
Criminal behavior is the result of psychological ills that may be remedied with treatment and hospitalization. Studies have revealed that many criminal men possess an XYY makeup. This means that they contain one extra Y chromosome that results in aggressive, deviant, and criminal behaviors. Further studies have revealed that these genetic abnormalities can alter hormonal secretion and lead to criminally deviant actions and behaviors. Increased serotonin levels can lead to aggressive tendencies while altered dopamine secretion can chemically reward the commitment of deviant acts by stimulating pleasure receptors.
Scientist 3
Criminal behavior is the result of neurological abnormalities that can be studied and mapped. Studies of criminal and non-criminal persons have revealed inconsistencies in brain scans and neurological makeup. These alterations in brain chemistry and function have resulted in the development of sociopathic and narcissistic tendencies. These tendencies often increase probabilities for deviant and violent outbursts. The best way to predict criminal behavior is to utilize neurological scanning and mapping procedures.
A new wave of research indicates that social forces shape possible deviant behaviors within humans. Legislators opt to use only this evidence to remedy issues associated with criminal tendencies. Assuming the information in the passage is correct, which of the following statements best describe this logic?
The logic is correct because criminal deviance is a social problem and should be corrected using social means.
This logic is fallacious because it is obvious that criminal behavior is the result of biological abnormalities.
The logic is correct because society shapes individuals into criminals despite their internal composition or chemistry.
This logic is fallacious because physical, psycological, nuerological, and social research can be used to better understand criminality.
This logic is fallacious because physical, psycological, nuerological, and social research can be used to better understand criminality.
This logic is fallacious because physical, psycological, nuerological, and social research can be used to better understand criminality.
This is the only correct answer. Weak cases may be made for the other choices but they still possess major issues in reasoning. The point of this question is to reveal that science is a discipline that depends on multiple views and researchers. Science is not limited to one view, method, or way of analysis. The most robust and well developed theories include evidence from an array of knowledge that support their strengths and highlight weaknesses.
Example Question #521 : Act Science
Passage I
An endocrinologist is a doctor who studies, diagnoses, and treats patients with hormone imbalances. There are many hormones involved in daily functioning. Two of the most important hormones for digestion are insulin and glucagon. These hormones are secreted by the pancreas. Insulin is released after a meal to help body cells take in sugar and covert it to energy. Glucagon is released when the body needs more energy, such as during exercise, and causes body cells to secrete sugar into the blood. A team of endocrinologists performed the following experiments:
Experiment 1
Five participants were given 15 grams of pure glucose (sugar). The participants had not eaten for four hours prior to the experiment. All five participants were healthy and had no serious medical conditions. A team of endocrinologists monitored the blood sugar and insulin levels of the participants over time. Figure 1 is a graph of the average levels in the five participants.
Experiment 2
Two participants were given 15 grams of pure glucose (sugar). The participants had not eaten for four hours prior to the experiment. One participant was healthy and the other had a hormone disease. Figure 2 is a graph of the blood sugar levels of the participants over time.
Diabetes is a disease where a person may need to take insulin to help the body cells take up blood sugar. According to the passage, when should a person with diabetes take insulin?
4 hours after eating
3 hours before eating
A person with diabetes should not take insulin.
5 hours before eating
1 hour before eating
1 hour before eating
Figure 1 depicts the average blood glucose and insulin concentrations for participants over a 5 hour period. At time 0, participants have ingested the tube of glucose. Figure 1 shows that glucose levels increase one hour after eating. Insulin levels increase two hours after eating.
The question clearly states that an individual with diabetes needs insulin, so one answer choice is already eliminated. Since there is a delay between eating, glucose level increase, and insulin increase, an individual would need to have insulin in their system before eating.
One hour before eating is a resonable time to take the insulin. Five hours before eating is much too early and may cause an unhealthy increase in blood sugar levels.
Example Question #11 : How To Find Experimental Design In Biology
Passage I
An endocrinologist is a doctor who studies, diagnoses, and treats patients with hormone imbalances. There are many hormones involved in daily functioning. Two of the most important hormones for digestion are insulin and glucagon. These hormones are secreted by the pancreas. Insulin is released after a meal to help body cells take in sugar and covert it to energy. Glucagon is released when the body needs more energy, such as during exercise, and causes body cells to secrete sugar into the blood. A team of endocrinologists performed the following experiments:
Experiment 1
Five participants were given 15 grams of pure glucose (sugar). The participants had not eaten for four hours prior to the experiment. All five participants were healthy and had no serious medical conditions. A team of endocrinologists monitored the blood sugar and insulin levels of the participants over time. Figure 1 is a graph of the average levels in the five participants.
Experiment 2
Two participants were given 15 grams of pure glucose (sugar). The participants had not eaten for four hours prior to the experiment. One participant was healthy and the other had a hormone disease. Figure 2 is a graph of the blood sugar levels of the participants over time.
Which Participant could have been a part of Experiment 1 and Experiment 2?
Participant B
Participant A
Participant A
The experiment summaries describe the requirements for participation. Experiment 1 involved all healthy subjects, which Experiment 2 involved one healthy and one unhealthy subject. Therefore, the healthy participant from Experiment 2 would have been able to participant in Experiment 1. Comparing the graphs of blood sugar levels in Figure 2, Participant A's levels most closely resemble the graph of blood sugar levels in Figure 1.
Example Question #19 : How To Find Experimental Design In Biology
Passage I
An endocrinologist is a doctor who studies, diagnoses, and treats patients with hormone imbalances. There are many hormones involved in daily functioning. Two of the most important hormones for digestion are insulin and glucagon. These hormones are secreted by the pancreas. Insulin is released after a meal to help body cells take in sugar and covert it to energy. Glucagon is released when the body needs more energy, such as during exercise, and causes body cells to secrete sugar into the blood. A team of endocrinologists performed the following experiments:
Experiment 1
Five participants were given 15 grams of pure glucose (sugar). The participants had not eaten for four hours prior to the experiment. All five participants were healthy and had no serious medical conditions. A team of endocrinologists monitored the blood sugar and insulin levels of the participants over time. Figure 1 is a graph of the average levels in the five participants.
Experiment 2
Two participants were given 15 grams of pure glucose (sugar). The participants had not eaten for four hours prior to the experiment. One participant was healthy and the other had a hormone disease. Figure 2 is a graph of the blood sugar levels of the participants over time.
Who/What was the "control" group in Experiment 2?
Glucose levels
Insulin levels
Participant A
15 grams of glucose
Participant B
Participant A
The control group for an experiment is an individual(s) that is(are) not exposed to the testing criteria. In Experiment 2, the control group was the healthy individual. Therefore, the correct answer is Participant A.
Example Question #20 : How To Find Experimental Design In Biology
A new drug is in its clinical trial phase. The graph below shows the data for participants sleep patterns before medication use and then after using the medication for three months. Series 1 shows the average hours slept a night for each participant prior to medication. Series 2 shows the average hours slept a night for each participant after three months of use. The average hours slept a night was obtained by recording sleep every night for one month, and then finding the average. Patients one through five took a placebo pill, not the actual Moonlight medication. Note: The y-axis is measured in hours slept a night, while the x-axis lists each anonymous patient numerically.
This experimental design is weakened by the fact that it does not take into account __________.
all of the answer choices given
external changes that could affect sleep over the couple months observed
the family dynamics of the participants
the eating habits of the participants
the exercise habits and stress level of the participants
all of the answer choices given
The study records a patient's total hours slept a night for one month after the patient has been on the medication for three months. A variety of factors could have happened that might account for the results. For example, if one patient just had a parent die during the one month recorded prior to medication, he or she might be sleeping less. Perhaps after 4 months, the patient is coping better and is able to sleep better. This experimental design would simply show an improvement in hours slept, but this improvement might not be due to the medication.
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