Sample Reading: Science Passages | The Complete SAT Course - Class 10 PDF Download

Introduction

The Reading: Science section of the SAT exam aims to assess the test-taker's ability to read and comprehend scientific texts, as well as analyze data and solve problems. The section includes passages from fields such as Earth science, biology, chemistry, and physics, along with related charts, graphs, or tables. Test-takers must demonstrate their ability to understand the main ideas, interpret data, and draw conclusions from the provided information.
In this document, we will explore the key concepts and strategies that will help you succeed in the Reading: Science section of the SAT exam. We will also provide sample questions and answers to help you better understand the types of questions you may encounter.

Key Concepts

• Understanding main ideas: Be able to identify the central theme or main idea of the passage, as well as the purpose of the author in writing the text.
• Vocabulary in context: Understand the meaning of scientific terms and phrases in the context of the passage.
• Data interpretation: Be able to read and interpret data from tables, graphs, and charts, and understand how they relate to the text.
• Making inferences: Draw conclusions based on the information provided in the passage and the data.
• Comparing and contrasting: Understand the similarities and differences between different ideas, theories, or experiments discussed in the passage.

Just as the Moon’s history was disrobed by laser ranging 50 years ago, Earth’s tropical forests are giving up their secrets to the light. Airborne light detection and ranging—called LiDAR—has over the last ten years become a key tool that ecologists use to understand physical variation in tropical forests across space and time. Like an MRI of the human brain, LiDAR probes the intricate three-dimensional architecture of the forest canopy, unveiling carbon that forests keep out of the atmosphere, and also the mounting threats to that carbon storehouse: drought, fire, clandestine logging and brash gold-mining operations. Even the quintessential natural disturbance of the sun-filled light gap—long thought to enhance the incredibly high species diversity of tropical forests—has been deconstructed by laser technology.

Laser ranging in tropical forests is such a game-changing technology that science results can scarcely get through peer-review before they are dwarfed by still larger-scale studies. In a decade, laser power on commercial-grade LiDARs has skyrocketed and costs have plummeted. These improvements in LiDAR technology allow airplanes to fly faster, higher and farther, covering more forest area in a single day than every ground-based survey that has ever been collected in the history of tropical ecology. To estimate the amount of carbon stored in a 50-hectare tropical forest monitoring plot on the ground—the largest field plot in the world—takes a team of 12 people about eight months: a slog of rain and mud and snakes with tape measures and data log books. Today’s airborne LiDARs can get you to within about 10% of the same carbon estimate in eight seconds.

It is this staggering contrast in scale between LiDAR and fieldwork that led us here: Before this decade is out, we could directly assess the carbon stock of every single square hectare of tropical forest on Earth. We could do it just as well as if we were standing there in the flesh with tape measures in hand. And we could do it for far less than what we have already spent to offset carbon emissions from forests. . . .

It is easy in principle, though logistically nightmarish, to measure carbon in tropical forests. A strict constructionist would cut, dry and weigh the biomass of the world’s forests. But this is a self-defeating enterprise. As a result, it is likely that no one has measured carbon over a single hectare of tropical forest, even with the most detailed field surveys. For a century ecologists and foresters have relied on allometric1 estimation in lieu of carbon measurements to translate field surveys of tree diameters, heights and wood densities into whole-forest carbon estimates. Given a volume with known dimensions and density, one would estimate its mass in a similar fashion.

As the new kid on the block, LiDAR has been tacked onto the back end—initially thought of as kind of large-scale helper to field surveys. Carbon estimates from the field have been treated as something inherently closer to the real thing than measurements made by LiDAR—ground “Truth” with a capital “T”. This is perhaps understandable historically, but vis-à-vis actual carbon, there is no such thing as ground truth: both field and LiDAR efforts rely on allometry to convert measurements into carbon estimates. Prior to using these measurements for carbon estimation, they exist as standardized, spatially explicit, archivable and verifiable data—the needed substrate for a REDD2-type accounting program.

Due to the constancy of the underlying measurements, both field and LiDAR data could provide the needed information if they covered every hectare on Earth. But, in the case of field surveys, this is impossible. The surveys that do exist measure a tiny amount of actual forest, and so what might be verified is widely spaced. And to avoid fraud and protect landowners, many governments keep their plot locations secret. Satellite LiDAR data remain sparse, providing only extrapolated, coarse-resolution carbon estimates with very high uncertainties, and there is no prospect of wall-to-wall coverage in the near future. By 2020, airborne LiDAR could give us a direct measurement of 3-D forest structure for every hectare in the tropics: a standardized database from which to build a carbon economy.

Beginning of reading passage footnotes.

• Pertaining to the study of changing proportions in part of an organism or body resulting from growth.
• Reduced Emissions from Deforestation and Degradation, a program implemented by the United Nations Framework Convention on Climate Change.

Carbon Biomass and Mean Canopy Height (MCH) in Different Types of Forests

The graph illustrates the relationship in different types of forests between mean canopy vertical height profiles (MCH), as measured by LiDAR, and field-based estimates of carbon biomass.

Q.1. The authors' central claim in the passage is that
(a) LiDAR’s opponents have prevented the technology from advancing to a point where it might be scientifically useful, favoring traditional methods.
(b) Fieldwork and LiDAR are best used in combination when mapping carbon in tropical forests, in order to avoid human error while maintaining accuracy.
(c) LiDAR is as important a technology as MRI scanning or the scientific study of the moon with lasers.
(d) LiDAR technology is faster, cheaper, and nearly as accurate as traditional field methods for measuring the carbon biomass on Earth.

Correct Answer is Option (d)
The passage discusses the use of LiDAR technology in mapping carbon in tropical forests and compares its effectiveness to traditional field methods. The authors argue that LiDAR technology is a valuable tool that can provide accurate results while being faster and cheaper than traditional methods. Therefore, the central claim of the passage is that LiDAR technology is a useful and efficient tool for measuring carbon biomass on Earth.

Q.2. In the first paragraph, the words “disrobed,” “unveiling” and “deconstructed” primarily serve to
(a) highlight the negative connotations that laser technology currently has.
(b) emphasize the extensive reach of laser technology.
(c) demonstrate the inherently unknowable characteristics of objects, even with laser technology.
(d) implicitly compare lasers to other forms of technology.

Correct Answer is Option (b)
The first paragraph describes the way that laser technology has enabled scientists to see and understand objects in new ways, revealing information that was previously hidden. The words "disrobed," "unveiling," and "deconstructed" are all used metaphorically to describe this process of revealing and understanding. Therefore, these words primarily serve to emphasize the extensive reach of laser technology and its ability to reveal new information about objects.

Q.3. The authors imply that the main benefit of using LiDAR, as opposed to fieldwork, for measuring carbon in tropical forests is the
(a) scale and rapidity with which LiDAR can be used.
(b) expense of hiring scientists to carry out fieldwork.
(c) rapid changes and improvements in LiDAR technology.
(d) precision of LiDAR, which eliminates human error.

Correct Answer is Option (a)
In paragraph 3, the authors state that LiDAR is a powerful tool that can cover hundreds of square kilometers in a day and can provide measurements with great accuracy, which is much faster than traditional fieldwork methods.

Q.4. Which choice provides the best evidence for the answer to the previous question?
(a) lines 16–18 (“In . . . plummeted”)(“In a decade, laser power on commercial-grade LiDARs has skyrocketed and costs have plummeted.”)
(b) lines 18–20 (“These . . . farther”)(“These improvements in LiDAR technology allow airplanes to fly faster, higher and farther,”)
(c) lines 30–32 (“Before . . . Earth”)(“Before this decade is out, we could directly assess the carbon stock of every single square hectare of tropical forest on Earth.”)
(d) lines 32–33 (“We could . . . hand”)(“We could do it just as well as if we were standing there in the flesh with tape measures in hand.”)

Correct Answer is Option (a)
This choice provides evidence for the authors' implication that LiDAR can be used with rapidity and at scale because it describes the technological improvements in LiDAR that have made it a more efficient and cost-effective tool for carbon estimation in tropical forests.

Q.5. As used in line 43 (“translate”), “translate” most nearly means
(a) convert
(b) move
(c) transform
(d) express

Correct Answer is Option (a)
In this context, "translate" means to convert data collected by LiDAR into estimates of carbon biomass.

Q.6. The authors use the phrase “ground “Truth” with a capital “T”” (lines 51–52 (“ground “Truth” with a capital “T”.”) in order to
(a) argue that field measurements should be given up in order to focus exclusively on LiDAR measurements.
(b) illustrate the impossibility of ever gaining accurate and usable measurements from either fieldwork or LiDAR.
(c) defend the idea that LiDAR measurements are inherently more accurate than measurements obtained via fieldwork.
(d) note the excessive faith scientists have put in the accuracy of field-survey estimates.

Correct Answer is Option (d)
The authors use the phrase "ground 'Truth' with a capital 'T'" to note the excessive faith scientists have put in the accuracy of field-survey estimates. This phrase is used to emphasize that there is no absolute "truth" or "accuracy" in carbon estimation, whether it is done through fieldwork or LiDAR.

Q.7. The authors imply that the response of various officials' attempts to measure their countries’ carbon stock through field surveys has been
(a) unhelpful, because they fear that jobs for their countries’ scientists will be lost.
(b) helpful, because their countries have invested significantly in technology to allow studies to expand.
(c) helpful, because their countries stand to benefit from universal carbon data that the studies will uncover.
(d) unhelpful, because they do not make their countries’ land holdings readily available for study.

Correct Answer is Option (c)
The authors imply that the response of various officials' attempts to measure their countries’ carbon stock through field surveys has been helpful, because their countries stand to benefit from universal carbon data that the studies will uncover. The authors note that some countries have invested significantly in technology to allow studies to expand, and this investment is likely to benefit them in the long run.

Q.8. Which choice provides the best evidence for the answer to the previous question?
(a) lines 59–61 (“Due . . . Earth”)(“Due to the constancy of the underlying measurements, both field and LiDAR data could provide the needed information if they covered every hectare on Earth.”)
(a) lines 62–64 (“The surveys . . . spaced”)(“The surveys that do exist measure a tiny amount of actual forest, and so what might be verified is widely spaced.”
(a) lines 64–65 (“And . . . secret”)(“And to avoid fraud and protect landowners, many governments keep their plot locations secret.”
(a) lines 65–68 (“Satellite . . . future”)(“Satellite LiDAR data remain sparse, providing only extrapolated, coarse-resolution carbon estimates with very high uncertainties, and there is no prospect of wall-to-wall coverage in the near future.”)

Correct Answer is Option (b)
This choice provides evidence for the authors' implication that officials' attempts to measure their countries’ carbon stock through field surveys have been unhelpful, because they do not make their countries’ land holdings readily available for study. The authors note that the surveys that do exist measure a tiny amount of actual forest, and what might be verified is widely spaced.

Q.9. The data in the graph support the authors' point in paragraph five (lines 47–58)(“As the new kid on the block, LiDAR has been tacked onto the back end—initially thought of as kind of large-scale helper to field surveys. Carbon estimates from the field have been treated as something inherently closer to the real thing than measurements made by LiDAR—ground “Truth” with a capital “T”. This is perhaps understandable historically, but vis-à-vis actual carbon, there is no such thing as ground truth: both field and LiDAR efforts rely on allometry to convert measurements into carbon estimates. Prior to using these measurements for carbon estimation, they exist as standardized, spatially explicit, archivable and verifiable data—the needed substrate for a REDD*-type accounting program.”) about the uses of LiDAR by
(a) providing an example of the use of information from LiDAR in conjunction with traditional field-based estimates.
(b) comparing data gathered by LiDAR technology from three separate forest sites.
(c) showing LiDAR’s superior accuracy compared to data gathered through fieldwork, even though the graph uses estimated figures.
(d) presenting an example of the use of LiDAR in a tropical forest, which until this study was purely hypothetical.

Correct Answer is Option (b)
The graph supports the authors' point in paragraph five about the uses of LiDAR by providing an example of the use of information from LiDAR in conjunction with traditional field-based estimates. The graph compares the carbon biomass estimates from LiDAR and fieldwork measurements in three different types of forests.

Q.10. It can reasonably be inferred from the graph that
(a) for the same mean canopy height (above 25MCH²), tropical forests have more carbon biomass than temperate forests.
(b) there is an inverse relationship between mean canopy vertical height and aboveground carbon biomass.
(c) at a mean canopy height of 625 MCH², all three types of forests depicted will have approximately the same aboveground carbon biomass.
(d) on average, the new tropical forest has less aboveground carbon biomass at a given canopy height than the boreal-temperate forest depicted.

Correct Answer is Option (b)
The graph shows an inverse relationship between mean canopy height and aboveground carbon biomass for the three types of forests depicted, which indicates that tropical forests have more carbon biomass than temperate forests, but this difference is due to their taller canopies.

Q.11. The information from the graph best supports the claim that the carbon biomass of the three forests depicted is most disparate at
(a) 25 MCH²
(b) 225 MCH²
(c) 400 MCH²
(d) 900 MCH²

Correct Answer is Option (c)
The information from paragraph five supports the inference that officials' attempts to measure their countries’ carbon stock through field surveys have been helpful, because their countries stand to benefit from universal carbon data that the studies will uncover. The paragraph notes that both LiDAR and fieldwork measurements can provide the needed substrate for a REDD-type accounting program, which suggests that officials are interested in using carbon.

The following passage is from a scientific article discussing the impact of climate change on coral reefs.
Coral reefs, often referred to as the "rainforests of the sea," are essential to the survival of many marine species. They provide shelter, breeding grounds, and feeding areas for a vast array of organisms. However, increasing ocean temperatures, a consequence of climate change, have led to the widespread coral bleaching, a phenomenon in which corals expel the symbiotic algae that provide them with nutrients and their vibrant colors.

Q.1. Which of the following best describes the main idea of the passage?
(a) Coral reefs are crucial for the survival of many marine species.
(b) Climate change has led to the destruction of coral reefs.
(c) Coral bleaching is a result of the expulsion of symbiotic algae from corals.
(d) The ocean's temperature is increasing due to climate change.

Correct Answer is Option (b)
The passage discusses the importance of coral reefs for marine species, how climate change has led to an increase in ocean temperatures, and the resulting coral bleaching. The main idea is that climate change is causing the destruction of coral reefs through the process of coral bleaching.

Q.2. According to the passage, why are coral reefs often referred to as the "rainforests of the sea"?
(a) They are found in the same geographical locations as rainforests.
(b) They both provide essential resources for the survival of various species.
(c) They share similar levels of biodiversity.
(d) Both coral reefs and rainforests are threatened by climate change.

Correct Answer is Option (b)
The passage states that coral reefs are essential to the survival of many marine species because they provide shelter, breeding grounds, and feeding areas. They are compared to rainforests because both ecosystems provide crucial resources for a diverse range of species.

The following graph illustrates the increasing ocean temperature over the past century.

Q.3. Which of the following statements about ocean temperature is supported by the information in the graph?
(a) The ocean temperature has remained relatively constant over the past century.
(b) The ocean temperature has decreased since 1900.
(c) The ocean temperature has increased by 1°C between 1900 and 2000.
(d) The ocean temperature has increased by more than 2°C between 1900 and 2010.

Correct Answer is Option (c)
The graph shows that the average ocean temperature was 15.2°C in 1900 and 16.0°C in 2000. This represents an increase of 1°C over the century.

Conclusion

To excel in the Reading: Science section of the SAT exam, it is essential to practice reading and understanding scientific texts, interpreting data, and drawing conclusions from the provided information. By mastering these skills, you will be well-prepared to tackle the diverse range of questions that may appear on the test.