ACT Science : How to find research summary in biology

Study concepts, example questions & explanations for ACT Science

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Example Questions

Example Question #241 : Act Science

Lynx_and_hare

Predator-prey relationships and mechanics are important tools for understanding the ecology of environments. Population cycles were first recorded in Canadian forests by fur trappers. Species interactions are important indicators of the health and economy of a natural environment. A twelve-year study of northern Canada revealed that snowshoe hares and lynxes share highly synchronized and predictable cycles. The lynx's predator populations mimic and mirrors that of their prey, the snowshoe hare. Two scientists express their views on these population patterns below.

Scientist 1

     The observed relationship is best explained by predator-prey relationships and competition for resources. Consumer-resource interactions fluctuate independently of variation within the environment.

Scientist 2

     The observed relationship is produced by environmental changes. Fluctuations in weather patterns and resources manipulate observed predator-prey relationships.

Based soley on the evidence in the graph, if the snowshoe hare suddenly becomes extinct, then which of the following would most likely happen to the lynx population?

Possible Answers:

The lynx population would rapidly decline.

The lynx population would decline rapidly and then begin to increase.

The lynx will population would increase.

The lynx population would adapt to a new food source.

Correct answer:

The lynx population would rapidly decline.

Explanation:

The question asked to only observe the graph and determine the suggested fate of the lynx population. Observation of the graph revealed that the populations mirror one another. Thus, if the hares disappear from the ecosystem, it is safe to conclude that the lynx population would decline.

Example Question #248 : Act Science

A mycologist performed an experiment to determine the effect of methanol on the mold Neurospora crassa.

1,500 Neurospora spores were divided evenly into five groups of three large glass test tubes each. Then each test tube was filled with 5.0 mL of liquid nutrient solution and either 0 mL, 0.5 mL, 1.0 mL, 1.5 mL, or 2.0 mL of methanol. The tubes were placed in an incubator at 28oC overnight to germinate, and then their aerial growth was marked beginning the next morning and every twelve hours thereafter for two days.

Table 1 shows the average growth data with  hours representing the morning after germination and  hours representing the end of the two-day experiment.

Table_science

Compared to the cultures with no methanol added, the growth of the cultures with 0.5 mL methanol added between 0 hours and 24 hours can be characterized as __________.

Possible Answers:

faster, then slower

faster only

slower only

slower, then faster

Correct answer:

faster, then slower

Explanation:

Table 1 shows that with 0.5 mL methanol added, the cultures with 0.5 mL methanol added grow 13 mm on average for the first 12 hours, while the cultures with no methanol added grow only 11 mm on average during that same period. So initially, we can characterize the growth of the 0.5 mL cultures as faster than the no-methanol-added group. But at 24 hours, the no-methanol cultures have grown to 20 mm on average, while the 0.5 mL added cultures have only grown to 16 mm on average. So, for these 12 hours, we can characterize the growth of the 0.5 mL cultures as faster than the no-methanol-added group. 

Table_science

Example Question #249 : Act Science

Two students present their ideas on species and populations, as well as their views on how species physically change over time. They also discuss phenomena that support their different models.

 

Student A

Within a population of individuals of a given species, there is little variation. All individuals are able to physically transform in ways that suit their needs. Physical change, such as the lengthening of a giraffe's neck, occurs over long periods of time because of a desire to modify one's characteristics. For example, in the past, giraffes likely found themselves surrounded by tall trees, and therefore had difficulty obtaining food on the tops of trees. In order to survive, they stretched their necks gradually to elongate them. Offspring inherited slightly longer necks, and, over time, giraffes developed unusually long necks. The fossil record indicates that giraffes in prehistoric times had significantly shorter necks compared to modern giraffes.

 

Student B

Any sizable population of individuals of a given species will contain noticeable variation. The physical characteristics of an individual are fixed. In a prehistoric population of hawks, for example, some individuals had powerful vision while others had weaker vision. The hawks competed with one another for food, and individuals with sharper vision were better equipped to spot small prey such as mice (their main source of food). Hawks with poorer vision, by contrast, had difficulty spotting prey and perished from starvation. The individuals with sharp vision passed on this desirable trait to their offspring, and, over time, hawks developed very keen eyesight. Analysis of the DNA from a prehistoric population of hawks has revealed significant differences between individuals in the genes that control eyesight.

 

The fossil record can reveal the shapes of eyeballs in a prehistoric population of hawks. Given that shape of the eyeball determines quality of vision, which student(s), if either, would expect to observe eyeballs of many different shapes in the population of prehistoric hawks?

Possible Answers:

Student B only

Neither Student A nor Student B

Student A only

Both Student A and Student B

Correct answer:

Student B only

Explanation:

Student B believes that variation exists in all sizable populations. Therefore, he/she would expect to see a wide range of vision quality in a prehistoric population of hawks.

Example Question #250 : Act Science

Two students present their ideas on species and populations, as well as their views on how species physically change over time. They also discuss phenomena that support their different models.

 

Student A

Within a population of individuals of a given species, there is little variation. All individuals are able to physically transform in ways that suit their needs. Physical change, such as the lengthening of a giraffe's neck, occurs over long periods of time because of a desire to modify one's characteristics. For example, in the past, giraffes likely found themselves surrounded by tall trees, and therefore had difficulty obtaining food on the tops of trees. In order to survive, they stretched their necks gradually to elongate them. Offspring inherited slightly longer necks, and, over time, giraffes developed unusually long necks. The fossil record indicates that giraffes in prehistoric times had significantly shorter necks compared to modern giraffes.

 

Student B

Any sizable population of individuals of a given species will contain noticeable variation. The physical characteristics of an individual are fixed. In a prehistoric population of hawks, for example, some individuals had powerful vision while others had weaker vision. The hawks competed with one another for food, and individuals with sharper vision were better equipped to spot small prey such as mice (their main source of food). Hawks with poorer vision, by contrast, had difficulty spotting prey and perished from starvation. The individuals with sharp vision passed on this desirable trait to their offspring, and, over time, hawks developed very keen eyesight. Analysis of the DNA from a prehistoric population of hawks has revealed significant differences between individuals in the genes that control eyesight.

 

Student A would argue which of the following about the DNA of a prehistoric population of giraffes?

Possible Answers:

There should be few differences between individuals in the genes that control neck length

There should be numerous differences between individuals in all genes

There should be absolutely no difference between individuals in all genes

There should be numerous differences between individuals in the genes that control neck length

Correct answer:

There should be few differences between individuals in the genes that control neck length

Explanation:

Student A believes that little variation in neck length existed within a prehistoric population of giraffes.  He or she would thus argue that the DNA pertaining to neck length should not vary much within a prehistoric population of giraffes.  Student A would consider the assertion "there should be absolutely no difference between individuals in all genes" to be extreme.

Example Question #251 : Act Science

Two students present their ideas on species and populations, as well as their views on how species physically change over time. They also discuss phenomena that support their different models.

 

Student A

Within a population of individuals of a given species, there is little variation. All individuals are able to physically transform in ways that suit their needs. Physical change, such as the lengthening of a giraffe's neck, occurs over long periods of time because of a desire to modify one's characteristics. For example, in the past, giraffes likely found themselves surrounded by tall trees, and therefore had difficulty obtaining food on the tops of trees. In order to survive, they stretched their necks gradually to elongate them. Offspring inherited slightly longer necks, and, over time, giraffes developed unusually long necks. The fossil record indicates that giraffes in prehistoric times had significantly shorter necks compared to modern giraffes.

 

Student B

Any sizable population of individuals of a given species will contain noticeable variation. The physical characteristics of an individual are fixed. In a prehistoric population of hawks, for example, some individuals had powerful vision while others had weaker vision. The hawks competed with one another for food, and individuals with sharper vision were better equipped to spot small prey such as mice (their main source of food). Hawks with poorer vision, by contrast, had difficulty spotting prey and perished from starvation. The individuals with sharp vision passed on this desirable trait to their offspring, and, over time, hawks developed very keen eyesight. Analysis of the DNA from a prehistoric population of hawks has revealed significant differences between individuals in the genes that control eyesight.

 

Which of the following findings, if true, could be used to counter the argument of Student B?

Possible Answers:

Within a modern population of hawks, there is moderate competition

Hawks of a prehistoric population did not compete with other species of birds

Within a prehistoric population of hawks, competition was high

Within a prehistoric population of hawks, competition was virtually nonexistent

Correct answer:

Within a prehistoric population of hawks, competition was virtually nonexistent

Explanation:

Student B argues that competition within prehistoric populations of hawks led to the propagation of powerful vision in hawks. Evidence that there was almost no competition in a prehistoric population of hawks would seriously weaken the argument of Student B.

Example Question #252 : Act Science

Two students present their ideas on species and populations, as well as their views on how species physically change over time. They also discuss phenomena that support their different models.

 

Student A

Within a population of individuals of a given species, there is little variation. All individuals are able to physically transform in ways that suit their needs. Physical change, such as the lengthening of a giraffe's neck, occurs over long periods of time because of a desire to modify one's characteristics. For example, in the past, giraffes likely found themselves surrounded by tall trees, and therefore had difficulty obtaining food on the tops of trees. In order to survive, they stretched their necks gradually to elongate them. Offspring inherited slightly longer necks, and, over time, giraffes developed unusually long necks. The fossil record indicates that giraffes in prehistoric times had significantly shorter necks compared to modern giraffes.

 

Student B

Any sizable population of individuals of a given species will contain noticeable variation. The physical characteristics of an individual are fixed. In a prehistoric population of hawks, for example, some individuals had powerful vision while others had weaker vision. The hawks competed with one another for food, and individuals with sharper vision were better equipped to spot small prey such as mice (their main source of food). Hawks with poorer vision, by contrast, had difficulty spotting prey and perished from starvation. The individuals with sharp vision passed on this desirable trait to their offspring, and, over time, hawks developed very keen eyesight. Analysis of the DNA from a prehistoric population of hawks has revealed significant differences between individuals in the genes that control eyesight.

 

Suppose it were discovered that a prehistoric population of hawks relied primarily on the carcasses of large animals for food. Would this discovery strengthen the argument of Student B?

Possible Answers:

No, because Student B argues that prehistoric hawks relied on eyesight to spot large prey.

Yes, because Student B argues that prehistoric hawks relied on eyesight to spot small prey.

No, because Student B argues that prehistoric hawks relied on eyesight to spot small prey.

Yes, because Student B argues that prehistoric hawks relied on eyesight to spot large prey.

Correct answer:

No, because Student B argues that prehistoric hawks relied on eyesight to spot small prey.

Explanation:

Student B argues that prehistoric hawks relied on eyesight to spot small prey. If it were discovered that these hawks primarily fed on carcasses of large animals and not small prey, the argument of Student B would be weakened.

Example Question #251 : Biology

Two students present their ideas on species and populations, as well as their views on how species physically change over time. They also discuss phenomena that support their different models.

 

Student A

Within a population of individuals of a given species, there is little variation. All individuals are able to physically transform in ways that suit their needs. Physical change, such as the lengthening of a giraffe's neck, occurs over long periods of time because of a desire to modify one's characteristics. For example, in the past, giraffes likely found themselves surrounded by tall trees, and therefore had difficulty obtaining food on the tops of trees. In order to survive, they stretched their necks gradually to elongate them. Offspring inherited slightly longer necks, and, over time, giraffes developed unusually long necks. The fossil record indicates that giraffes in prehistoric times had significantly shorter necks compared to modern giraffes.

 

Student B

Any sizable population of individuals of a given species will contain noticeable variation. The physical characteristics of an individual are fixed. In a prehistoric population of hawks, for example, some individuals had powerful vision while others had weaker vision. The hawks competed with one another for food, and individuals with sharper vision were better equipped to spot small prey such as mice (their main source of food). Hawks with poorer vision, by contrast, had difficulty spotting prey and perished from starvation. The individuals with sharp vision passed on this desirable trait to their offspring, and, over time, hawks developed very keen eyesight. Analysis of the DNA from a prehistoric population of hawks has revealed significant differences between individuals in the genes that control eyesight.

 

Which of the following best explains why Student A mentioned the fossil record?

Possible Answers:

The fossil record serves as evidence of the significant variation within a prehistoric population of giraffes

The fossil record serves as evidence of the lack of variation within a prehistoric population of giraffes

The fossil record serves as evidence of the competition between giraffes of a prehistoric population

The fossil record serves as evidence of the change in giraffe neck length over time

Correct answer:

The fossil record serves as evidence of the change in giraffe neck length over time

Explanation:

Student A mentions the fossil record to support the idea that giraffe neck length has changed over time. He/she argues that the fossil record shows how giraffes in prehistoric times had much shorter necks compared to modern giraffes.

Example Question #254 : Act Science

Two students present their ideas on species and populations, as well as their views on how species physically change over time. They also discuss phenomena that support their different models.

 

Student A

Within a population of individuals of a given species, there is little variation. All individuals are able to physically transform in ways that suit their needs. Physical change, such as the lengthening of a giraffe's neck, occurs over long periods of time because of a desire to modify one's characteristics. For example, in the past, giraffes likely found themselves surrounded by tall trees, and therefore had difficulty obtaining food on the tops of trees. In order to survive, they stretched their necks gradually to elongate them. Offspring inherited slightly longer necks, and, over time, giraffes developed unusually long necks. The fossil record indicates that giraffes in prehistoric times had significantly shorter necks compared to modern giraffes.

 

Student B

Any sizable population of individuals of a given species will contain noticeable variation. The physical characteristics of an individual are fixed. In a prehistoric population of hawks, for example, some individuals had powerful vision while others had weaker vision. The hawks competed with one another for food, and individuals with sharper vision were better equipped to spot small prey such as mice (their main source of food). Hawks with poorer vision, by contrast, had difficulty spotting prey and perished from starvation. The individuals with sharp vision passed on this desirable trait to their offspring, and, over time, hawks developed very keen eyesight. Analysis of the DNA from a prehistoric population of hawks has revealed significant differences between individuals in the genes that control eyesight.

 

Both students would likely agree that significant changes in species occur over __________.

Possible Answers:

a couple of years

several weeks

a single generation

many generations

Correct answer:

many generations

Explanation:

Both students refer to prehistoric populations of species, suggesting that change in species occurs over many generations.

Example Question #255 : Act Science

Elena is conducting an experiment to determine the effect of a new drug, norzapam, that is meant to help diabetic patients produce insulin naturally. She has four test subjects, all with type 1 diabetes, and all of whom continued to take fast-acting insulin as needed but ceased taking long-acting insulin. Two patients received the drug and two received a placebo. Over a period of ten months Elena measured her patients’ insulin levels each day (measured in International Units) and averaged them for each month. She also asked each patient to walk for as long as they could after taking the drug before their blood sugar dropped too low to continue. Her results from the experiment are shown in the given tables.

Patient 1: Drug received

Patient 1 is a 45 year-old male who is overweight and leads a sedentary lifestyle.

Month

Insulin level (IU)

Length of Walk (min)

1

50

15

2

52

18

3

54

20

4

60

20

5

64

22

6

70

25

7

78

28

8

86

33

9

98

38

10

103

40

 

Patient 2: Drug received

Patient 2 is a 23 year-old female of healthy weight who leads an active lifestyle.

Month

Insulin level (IU)

Length of Walk (min)

1

50

30

2

55

38

3

59

42

4

68

47

5

75

55

6

83

60

7

90

68

8

97

70

9

105

72

10

112

75

 

Patient 3: No drug

Patient 3 is a 60 year-old female who is overweight and leads a moderately active lifestyle.

Month

Insulin level (IU)

Length of Walk (min)

1

50

25

2

51

25

3

53

28

4

51

25

5

53

28

6

55

30

7

53

28

8

65

33

9

51

25

10

50

25

 

Patient 4: No Drug

Patient 4 is a 28 year-old male of healthy weight who leads very active lifestyle.

Month

Insulin level (IU)

Length of Walk (min)

1

60

45

2

65

48

3

68

50

4

68

50

5

70

55

6

71

56

7

68

52

8

69

55

9

79

65

10

80

65

Is there enough evidence to prove the drug causes insulin levels to be raised?

Possible Answers:

Yes, the results are consistent with this conclusion

No, there were not enough men sampled

No, there was no control group

No, more people should have been sampled

Correct answer:

No, more people should have been sampled

Explanation:

To prove causation one needs to experiment with a large, randomized sample of people. While this could have been a causal experiment, Elena lacked that. There is no evidence that suggests she randomly sampled people for her experiment. Also, there are too many possible confounding variables that she has not addressed. 

Example Question #256 : Act Science

Elena is conducting an experiment to determine the effect of a new drug, norzapam, that is meant to help diabetic patients produce insulin naturally. She has four test subjects, all with type 1 diabetes, and all of whom continued to take fast-acting insulin as needed but ceased taking long-acting insulin. Two patients received the drug and two received a placebo. Over a period of ten months Elena measured her patients’ insulin levels each day (measured in International Units) and averaged them for each month. She also asked each patient to walk for as long as they could after taking the drug before their blood sugar dropped too low to continue. Her results from the experiment are shown in the given tables.

Patient 1: Drug received

Patient 1 is a 45 year-old male who is overweight and leads a sedentary lifestyle.

Month

Insulin level (IU)

Length of Walk (min)

1

50

15

2

52

18

3

54

20

4

60

20

5

64

22

6

70

25

7

78

28

8

86

33

9

98

38

10

103

40

 

Patient 2: Drug received

Patient 2 is a 23 year-old female of healthy weight who leads an active lifestyle.

Month

Insulin level (IU)

Length of Walk (min)

1

50

30

2

55

38

3

59

42

4

68

47

5

75

55

6

83

60

7

90

68

8

97

70

9

105

72

10

112

75

 

Patient 3: No drug

Patient 3 is a 60 year-old female who is overweight and leads a moderately active lifestyle.

Month

Insulin level (IU)

Length of Walk (min)

1

50

25

2

51

25

3

53

28

4

51

25

5

53

28

6

55

30

7

53

28

8

65

33

9

51

25

10

50

25

 

Patient 4: No Drug

Patient 4 is a 28 year-old male of healthy weight who leads very active lifestyle.

Month

Insulin level (IU)

Length of Walk (min)

1

60

45

2

65

48

3

68

50

4

68

50

5

70

55

6

71

56

7

68

52

8

69

55

9

79

65

10

80

65

What could have caused the dip in insulin levels for patient 3 during months 9 and 10?

Possible Answers:

A medical concern

A change in walking habits

A change in eating habits

A divorce

Correct answer:

A medical concern

Explanation:

We know patient 3 didn't change her walking habits as we have evidence she walked a number of minutes each day. We have no data on eating habits, nor personal life, such as divorce.. The only likely possibility is that she had a medical concern that briefly change her biology and affected insulin levels. 

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