ACT Reading : Drawing Inferences from Natural Science Passages

Study concepts, example questions & explanations for ACT Reading

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Example Questions

Example Question #21 : Making Inferences About The Author Or Natural Science Passage Content

"Cacti" by Ami Dave (2013)

Cacti are plants suited to the desert, and we must always keep this factor in mind when growing ornamental cacti in our gardens, for it helps us provide cacti with conditions that allow them to survive and thrive. For example, a cactus should never be watered over its body, as it will start to rot. This is because it is covered with a waxy coating which prevents water loss through evaporation. When one waters the cactus over its body, the waxy coating is washed away and the plant begins to rot. The amount of water that one must supply to the cactus is very much dependent upon the season and upon the climate of the place. During the summer season one should water cacti every four days, whereas in the rainy season, once every fifteen days is quite enough.

Cacti need a minimum of two and a half hours of sunlight per day; however, they should not be kept in the sun all day because they may wrinkle when exposed to too much bright sunlight. Unlike other plants, cacti produce carbon dioxide during the day and oxygen during the night, so they are ideal plants to be kept in bedrooms to freshen up the air at night.

If a cactus is to thrive and prosper, the size of the pot in which it is grown needs to be monitored carefully. The pot should always be a little smaller than the plant itself because it is only when the plant has to struggle to survive that it will thrive. If the pot is too spacious and the plant does not need to struggle, chances are that the cactus will die. Similarly, if a cactus shows no signs of growth, stop watering it. Watering should be resumed only when the plant begins to grow again.

The substrata of a cactus pot is ideally composed of pieces of broken bricks at the bottom, followed by a layer of charcoal above the bricks, and then coarse sand and pebbles above the charcoal. Leaf mould is the best manure.

Grafting cacti is very simple. A very small piece of the cactus plant should be stuck with tape to the plant that needs grafting. The smaller the piece, the easier it is to graft. To reproduce cacti, one has to simply cut off a piece of the cactus, allow it to dry for a few days, and then place it over the cacti substrate. It will automatically develop roots.

It is very easy to differentiate between cacti and other plants that look like cacti. All cacti have fine hair at the base of each thorn. The so-called “thorns” are in fact highly modified leaves which prevent loss of water through transpiration. If one ever gets pricked by cacti thorns, one should take tape, place it over the area where the thorns have penetrated the skin, and then peel it off. All of the thorns will get stuck to the tape and will be removed.

The passage is most likely an excerpt from what type of document?

Possible Answers:

A manual about how to grow cacti at home

A science textbook

A personal anecdote about cacti 

A descriptive panel at a botanical garden

An informational brochure

Correct answer:

A manual about how to grow cacti at home

Explanation:

It most likely comes from a how-to manual, since it outlines the steps for planting and nurturing a cactus as it grows. A brochure would not contain quite as much information, and would not be detailed. A botanical garden would address the lineage of the plant and more about its genus and species, rather than how to grow it. A science textbook would explore the scientific analysis of the plant, such as how it obtains energy through photosynthesis and more facts along those lines. A personal anecdote about cacti would not need to give any information about how to grow one.

Example Question #1 : Making Inferences In Narrative Science Passages

"Cacti" by Ami Dave (2013)

Cacti are plants suited to the desert, and we must always keep this factor in mind when growing ornamental cacti in our gardens, for it helps us provide cacti with conditions that allow them to survive and thrive. For example, a cactus should never be watered over its body, as it will start to rot. This is because it is covered with a waxy coating which prevents water loss through evaporation. When one waters the cactus over its body, the waxy coating is washed away and the plant begins to rot. The amount of water that one must supply to the cactus is very much dependent upon the season and upon the climate of the place. During the summer season one should water cacti every four days, whereas in the rainy season, once every fifteen days is quite enough.

Cacti need a minimum of two and a half hours of sunlight per day; however, they should not be kept in the sun all day because they may wrinkle when exposed to too much bright sunlight. Unlike other plants, cacti produce carbon dioxide during the day and oxygen during the night, so they are ideal plants to be kept in bedrooms to freshen up the air at night.

If a cactus is to thrive and prosper, the size of the pot in which it is grown needs to be monitored carefully. The pot should always be a little smaller than the plant itself because it is only when the plant has to struggle to survive that it will thrive. If the pot is too spacious and the plant does not need to struggle, chances are that the cactus will die. Similarly, if a cactus shows no signs of growth, stop watering it. Watering should be resumed only when the plant begins to grow again.

The substrata of a cactus pot is ideally composed of pieces of broken bricks at the bottom, followed by a layer of charcoal above the bricks, and then coarse sand and pebbles above the charcoal. Leaf mould is the best manure.

Grafting cacti is very simple. A very small piece of the cactus plant should be stuck with tape to the plant that needs grafting. The smaller the piece, the easier it is to graft. To reproduce cacti, one has to simply cut off a piece of the cactus, allow it to dry for a few days, and then place it over the cacti substrate. It will automatically develop roots.

It is very easy to differentiate between cacti and other plants that look like cacti. All cacti have fine hair at the base of each thorn. The so-called “thorns” are in fact highly modified leaves which prevent loss of water through transpiration. If one ever gets pricked by cacti thorns, one should take tape, place it over the area where the thorns have penetrated the skin, and then peel it off. All of the thorns will get stuck to the tape and will be removed.

Which of the following can be inferred from the information provided in the passage?

Possible Answers:

Cacti follow a respiration cycle that is different than that of other plants.

Pot size is not an important factor in cactus growth.

It is difficult to distinguish cacti from other plants.

People have been growing cacti in their homes for hundreds of years.

Cacti are found in every desert known to man.

Correct answer:

Cacti follow a respiration cycle that is different than that of other plants.

Explanation:

The second paragraph states that, unlike other plants, cacti produce CO2 during the day and O2 during the night, making them good plants to freshen the air when one is sleeping. Thus, it can be inferred that cacti have a unique respiration cycle, compared to other plants. The other answer choices are not inferences that can be made from the passage. The passage states that pot size is indeed a factor is growth, and the last paragraph mentions how it is easy to tell cacti apart from other plants. While the passage does mention that the cactus is a desert plant, nowhere does it say that cacti are found in EVERY desert. Similarly, the passage provides no information about for how long people have been growing cacti in their homes.

Example Question #1 : Context Dependent Meaning Of Phrases Or Sentences In Natural Science Passages

"Cacti" by Ami Dave (2013)

Cacti are plants suited to the desert and we must keep this factor in mind always when growing ornamental cacti in our gardens, for it helps in the survival of the plant. For example, a cactus should never be watered over its body as it will start to rot. This is because it is covered with a waxy coating which prevents water loss through evaporation. When one waters the cactus over its body, the waxy coating is washed away and the plant begins to rot. The amount of water that you must supply to the cactus is very much dependent upon the season and upon the climate of the place. During the summer season one should water cacti every four days whereas in the rainy season once every fifteen days is quite enough.

Cacti need a minimum of two and a half hours of sunlight per day. However they should not be kept all day in the sun because they may wrinkle in too much of bright sunlight. Unlike other plants cacti produce carbon dioxide during the day and oxygen during the night. Hence, they are ideal plants to be kept in bedrooms to freshen up the air at night.

If the cactus plant is to thrive and prosper, the size of the pot in which it is grown has to be carefully monitored. The pot should always be a little smaller than the plant itself because it is only when the plant has to struggle to survive that it will thrive. If the pot is too spacious the struggle element is removed and the chances are that the cactus will die. Cacti are like human beings. When they suffer they will grow. Similarly if a cactus shows no signs of growth, stop the watering. It should be resumed only when the plant resumes growth.

The substrata of a cactus pot is ideally composed of pieces of broken bricks at the bottom, charcoal above it, then coarse sand and pebbles above it. Leaf mould is the best manure.

Grafting of cacti is very simple. A very small piece of the cactus plant should be stuck with cellotape to the plant that needs grafting. The smaller the piece the easier it is to graft. To reproduce cacti, one has to simply cut off a piece of the cactus, allow it to dry for a few days and then just place it over the cacti substrate. It will automatically develop roots.

To differentiate between cacti and other plants that look like cacti is very easy. All cacti have fine hair at the base of each thorn. The so-called thorns are in fact highly modified leaves which prevent loss of water through transpiration. If one ever gets pricked by cacti thorns, one should take cellotape, place it over the area where the thorns have penetrated the skin and then peel it off. All the thorns will get stuck to the cellotape and will be removed.

If the author were to add the underlined sentences, "Cacti are like human beings. When they suffer they will grow," to the third paragraph, what would these lines mean in context?

Possible Answers:

A suffering cactus will grow more quickly.

By providing oxygen, cacti help sustain human life.

Cacti and humans endure similar levels of suffering.

Overcoming the obstacles of life is the most significant factor that influences the maturity of an individual.

Cacti and humans have no traits in common.

Correct answer:

Overcoming the obstacles of life is the most significant factor that influences the maturity of an individual.

Explanation:

By making this statement, the author is suggesting that struggles and suffering result in individual growth. Thus, the most reasonable implication is that overcoming obstacles leads to maturity. The passage does not mention anything about the levels of suffering that human and cacti go through, nor does it say that they are similar.

Example Question #11 : Drawing Inferences From Natural Science Passages

"The Multiple Sides of Computer Science" by Matthew Minerd (2014)

It often takes some time for a new discipline to become recognized as an independent science. An excellent example of this is computer science. In many ways, this science still is a hodgepodge of several different sciences, each one having its own distinct character. For example, some computer scientists are almost indistinguishable from mathematicians. Many of the most difficult topics in pattern recognition and data communications require intensive mathematics in order to provide software solutions. Years of training in the appropriate disciplines are necessary before the computer scientist can even begin to work as a programmer in such areas. In contrast to those computer scientists who work with complex mathematics, many computer scientists work on areas of hardware development that are similar to disciplines like electrical engineering and physics.

However, computer science has its own particular problems regarding the unity of its subject matter. There are many practical applications for computing work; therefore, many computer scientists focus on learning a large set of skills in programming languages, development environments, and even information technology. All of these disciplines have a certain practical coloration that is quite distinct from the theoretical concepts used in other parts of the field. Nevertheless, these practical topics add to the broad range of topics covered by most academic programs that claim to focus on “computer science.” It can only be hoped that these disciplines will increase in orderliness in the coming decades.

Which of the following topics would not be a good example to add to the second paragraph?

Possible Answers:

Applications of computing to civic planning

Courses in manufacturing and connecting internet cables

Topics related to building new computers from parts

Studies in the types of physics involved in memory chip design

Studies of the social ramifications of programming

Correct answer:

Studies in the types of physics involved in memory chip design

Explanation:

The second paragraph focuses on the practical topics that often are taught in computer science programs. (These are contrasted to the more "theoretical" or "scientific" topics noted in the first paragraph.) The only really "scientific" topic listed here is the one about the physics involved in designing memory chips. Since this focuses on the physics, it is not so much about how to make these things as it is about the reasons why they work. This is more of a speculative matter than a practical or technical one.

Example Question #1 : Making Inferences About The Author Or Natural Science Passage Content

"The Multiple Sides of Computer Science" by Matthew Minerd (2014)

It often takes some time for a new discipline to become recognized as an independent science. An excellent example of this is computer science. In many ways, this science still is a hodgepodge of several different sciences, each one having its own distinct character. For example, some computer scientists are almost indistinguishable from mathematicians. Many of the most difficult topics in pattern recognition and data communications require intensive mathematics in order to provide software solutions. Years of training in the appropriate disciplines are necessary before the computer scientist can even begin to work as a programmer in such areas. In contrast to those computer scientists who work with complex mathematics, many computer scientists work on areas of hardware development that are similar to disciplines like electrical engineering and physics.

However, computer science has its own particular problems regarding the unity of its subject matter. There are many practical applications for computing work; therefore, many computer scientists focus on learning a large set of skills in programming languages, development environments, and even information technology. All of these disciplines have a certain practical coloration that is quite distinct from the theoretical concepts used in other parts of the field. Nevertheless, these practical topics add to the broad range of topics covered by most academic programs that claim to focus on “computer science.” It can only be hoped that these disciplines will increase in orderliness in the coming decades.

Based on this passage, which of the following might be true about the early history of modern physics?

Possible Answers:

It had a very practical component

None of these

It was often combined with many topics studied in philosophy

It was uninteresting to most people

It was underdeveloped and primitive

Correct answer:

It was often combined with many topics studied in philosophy

Explanation:

The basic point of this selection is that sciences tend to be somewhat "hazy" in their early years. They do not have defined boundaries and tend to deal with many topics. It is actually true that early modern physics tended to deal with many topics of "natural philosophy."  Only with time did it define its own topics clearly.  We are still waiting for this in computer science (or at least the passage implies this).

Example Question #1 : Textual Relationships In Science Passages

"The Multiple Sides of Computer Science" by Matthew Minerd (2014)

It often takes some time for a new discipline to become recognized as an independent science. An excellent example of this is computer science. In many ways, this science still is a hodgepodge of several different sciences, each one having its own distinct character. For example, some computer scientists are almost indistinguishable from mathematicians. Many of the most difficult topics in pattern recognition and data communications require intensive mathematics in order to provide software solutions. Years of training in the appropriate disciplines are necessary before the computer scientist can even begin to work as a programmer in such areas. In contrast to those computer scientists who work with complex mathematics, many computer scientists work on areas of hardware development that are similar to disciplines like electrical engineering and physics.

However, computer science has its own particular problems regarding the unity of its subject matter. There are many practical applications for computing work; therefore, many computer scientists focus on learning a large set of skills in programming languages, development environments, and even information technology. All of these disciplines have a certain practical coloration that is quite distinct from the theoretical concepts used in other parts of the field. Nevertheless, these practical topics add to the broad range of topics covered by most academic programs that claim to focus on “computer science.” It can only be hoped that these disciplines will increase in orderliness in the coming decades.

What might we infer about computer science studies from the underlined sentence?

Possible Answers:

None of the other answers

The computer science courses are all mathematical in nature, making computer science majors appear to be mathematics majors. 

They are often followed by a good deal of mathematics to explain the topics covered in general computer science courses.

You often take no computing courses until late into your studies of computer science.

They often require many mathematics courses to prepare for the "real" work of computer science.

Correct answer:

They often require many mathematics courses to prepare for the "real" work of computer science.

Explanation:

The sentence states that someone is only truly a programmer after all the necessary math is taken by the computer science student. This does not necessarily mean that the student takes no computing courses. It only means that a computer science student is truly a programmer after the math courses are mastered.

Example Question #361 : Hspt Reading

Adapted from An Introduction to Astronomy by Forest Ray Moulton (1916 ed.)

The ancient Greeks, at a period four or five hundred years preceding the common era, definitely undertook to find from systematic observation how celestial phenomena follow one another. They determined very accurately the number of days in the year, the period of the moon's revolution, and the paths of the sun and the moon among the stars; they correctly explained the cause of eclipses and learned how to predict them with a considerable degree of accuracy; they undertook to measure the distances to the heavenly bodies, and to work out a complete system that would represent their motions. The idea was current among the Greek philosophers that the earth was spherical, that it turned on its axis, and, among some of them, that it revolved around the sun. They had true science in the modern acceptance of the term, but it was largely confined to the relations among celestial phenomena.

The conception that the heavens are orderly, which they definitely formulated and acted on with remarkable success, has been extended, especially in the last two centuries, so as to include the whole universe. The extension was first made to the inanimate world and then to the more complicated phenomena associated with living beings. Every increase in carefully recorded experience has confirmed and strengthened the belief that nature is perfectly orderly, until now every one who has had an opportunity of becoming familiar with any science is firmly convinced of the truth of this principle, which is the basis of all science.

Based on the passage, which of the following would cause the end of all science if it were true?

Possible Answers:

The arrogance of unmethodical scientists

The ignorance of superstitious people

A lack of patterns in natural phenomena

A strict focus on celestial phenomena

None of the other answers

Correct answer:

A lack of patterns in natural phenomena

Explanation:

The last paragraph stresses the role of orderliness in making science possible. If the phenomena of the world did not exhibit regularity, it would be impossible for there to be science at all. That is, where there is no law seen, there will be no law recorded. 

Example Question #1 : Extrapolating From The Text In Natural Science Passages

"Darwinism's Effect on Science" by Matthew Minerd (2014)

For much of the history of human thought, the sciences have studied subjects that seemed to be eternal and unchanging. Even the basic laws of the Nile’s flooding were investigated in the hopes of finding never-altering laws. Similarly, the scientific investigations of the ancient Near East and Greece into the regular laws of the stars ultimately looked for constant patterns. This overall pattern of scientific reasoning has left deep marks on the minds of almost all thinkers and found its apotheosis in modern physics. From the time of the early renaissance to the nineteenth century, physics represented the ultimate expression of scientific investigation for almost all thinkers. Its static laws appeared to be the unchanging principles of all motion and life on earth. By the nineteenth century, it had appeared that only a few details had to be “cleared up” before all science was basically known.

In many ways, this situation changed dramatically with the arrival of Darwinism. It would change even more dramatically in early twentieth-century physics as well. Darwin’s theories of evolution challenged many aspects of the “static” worldview. Even those who did not believe that a divine being created an unchanging world were shaken by the new vistas opened up to science by his studies. It had been a long-accepted inheritance of Western culture to believe that the species of living organisms were unchanging in nature. Though there might be many different kinds of creatures, the kinds themselves were not believed to change. The thesis of a universal morphing of types shattered this cosmology, replacing the old world-view with a totally new one. Among the things that had to change in light of Darwin’s work was the very view of science held by most people.

Which of the following is implied in this passage about modern physics?

Possible Answers:

It was singularly new in the history of scientific thought.

It was viewed as the science that explained all others.

It was freed of superstition during the Renaissance.

It was dogmatically tied to Renaissance ideas.

None of the other answers

Correct answer:

It was viewed as the science that explained all others.

Explanation:

The best sentence for answering this question is, "Its static laws appeared to be the unchanging principles of all motion and life on earth." The first paragraph implies that physics appeared to provide the principles needed for explaining all things. It would therefore appear to many to be the "science of sciences." (Indeed, this has been the temptation in real history as well, though that is another, complex story!)

Example Question #1 : Extrapolating From The Text In Natural Science Passages

"Darwinism's Effect on Science" by Matthew Minerd (2014)

For much of the history of human thought, the sciences have studied subjects that seemed to be eternal and unchanging. Even the basic laws of the Nile’s flooding were investigated in the hopes of finding never-altering laws. Similarly, the scientific investigations of the ancient Near East and Greece into the regular laws of the stars ultimately looked for constant patterns. This overall pattern of scientific reasoning has left deep marks on the minds of almost all thinkers and found its apotheosis in modern physics. From the time of the early renaissance to the nineteenth century, physics represented the ultimate expression of scientific investigation for almost all thinkers. Its static laws appeared to be the unchanging principles of all motion and life on earth. By the nineteenth century, it had appeared that only a few details had to be “cleared up” before all science was basically known.

In many ways, this situation changed dramatically with the arrival of Darwinism. It would change even more dramatically in early twentieth-century physics as well. Darwin’s theories of evolution challenged many aspects of the “static” worldview. Even those who did not believe that a divine being created an unchanging world were shaken by the new vistas opened up to science by his studies. It had been a long-accepted inheritance of Western culture to believe that the species of living organisms were unchanging in nature. Though there might be many different kinds of creatures, the kinds themselves were not believed to change. The thesis of a universal morphing of types shattered this cosmology, replacing the old world-view with a totally new one. Among the things that had to change in light of Darwin’s work was the very view of science held by most people.

Who was most affected by the changes caused by Darwinism?

Possible Answers:

Publishers of science texts

Science teachers

Religious believers

Religious zealots

None of the other answers

Correct answer:

None of the other answers

Explanation:

There have almost always been controversies about evolution, lasting to our day. Do not bring any of this to your reading of the passage; stick to the text. The general implication in the second paragraph is that everyone was affected by these changes in outlook—believers and non-believers alike. None of the limited groups listed in the answers is sufficient. Therefore, the best choice is "none of the other answers."

Example Question #1 : Making Inferences In Natural Science Passages

"Darwinism's Effect on Science" by Matthew Minerd (2014)

For much of the history of human thought, the sciences have studied subjects that seemed to be eternal and unchanging. Even the basic laws of the Nile’s flooding were investigated in the hopes of finding never-altering laws. Similarly, the scientific investigations of the ancient Near East and Greece into the regular laws of the stars ultimately looked for constant patterns. This overall pattern of scientific reasoning has left deep marks on the minds of almost all thinkers and found its apotheosis in modern physics. From the time of the early renaissance to the nineteenth century, physics represented the ultimate expression of scientific investigation for almost all thinkers. Its static laws appeared to be the unchanging principles of all motion and life on earth. By the nineteenth century, it had appeared that only a few details had to be “cleared up” before all science was basically known.

In many ways, this situation changed dramatically with the arrival of Darwinism. It would change even more dramatically in early twentieth-century physics as well. Darwin’s theories of evolution challenged many aspects of the “static” worldview. Even those who did not believe that a divine being created an unchanging world were shaken by the new vistas opened up to science by his studies. It had been a long-accepted inheritance of Western culture to believe that the species of living organisms were unchanging in nature. Though there might be many different kinds of creatures, the kinds themselves were not believed to change. The thesis of a universal morphing of types shattered this cosmology, replacing the old world-view with a totally new one. Among the things that had to change in light of Darwin’s work was the very view of science held by most people.

Given Darwin's statements, which of the following should be expected?

Possible Answers:

Human beings will likely all die in a massive nuclear war.

Humanity as it is today has reached its fixed state.

Ancient physics was completely worthless.

Although we do not train bears as pets today, we may well in years to come.

There were no dogs at one time in the earth's history.

Correct answer:

There were no dogs at one time in the earth's history.

Explanation:

The second paragraph of this selection mostly discusses the fact that Darwin's theories lead to the belief in the changing of creatures over time. This means that some species may never have existed. Also, it implies that new ones might have arisen. Therefore, among the options provided, the best answer is the one that says that perhaps dogs did not at one time exist.

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