1. Ocean acidification, often described as the "other" carbon dioxide problem, occurs when the ocean absorbs excess CO2 from the atmosphere, lowering the pH of seawater. While the change in pH may seem small, it has a disproportionate effect on marine organisms that build shells or skeletons from calcium carbonate, such as corals and certain plankton species. Scientists warn that if current emission trends continue, some marine ecosystems could face irreversible damage within decades, with consequences that extend well beyond the ocean itself, including impacts on global fisheries and coastal communities that depend on them. What is the main topic of this passage?

2. Ocean acidification, often described as the "other" carbon dioxide problem, occurs when the ocean absorbs excess CO2 from the atmosphere, lowering the pH of seawater. While the change in pH may seem small, it has a disproportionate effect on marine organisms that build shells or skeletons from calcium carbonate, such as corals and certain plankton species. Scientists warn that if current emission trends continue, some marine ecosystems could face irreversible damage within decades, with consequences that extend well beyond the ocean itself, including impacts on global fisheries and coastal communities that depend on them. According to the passage, ocean acidification is caused by what?

3. Ocean acidification, often described as the "other" carbon dioxide problem, occurs when the ocean absorbs excess CO2 from the atmosphere, lowering the pH of seawater. While the change in pH may seem small, it has a disproportionate effect on marine organisms that build shells or skeletons from calcium carbonate, such as corals and certain plankton species. Scientists warn that if current emission trends continue, some marine ecosystems could face irreversible damage within decades, with consequences that extend well beyond the ocean itself, including impacts on global fisheries and coastal communities that depend on them. Which organisms are described as particularly vulnerable?

4. Ocean acidification, often described as the "other" carbon dioxide problem, occurs when the ocean absorbs excess CO2 from the atmosphere, lowering the pH of seawater. While the change in pH may seem small, it has a disproportionate effect on marine organisms that build shells or skeletons from calcium carbonate, such as corals and certain plankton species. Scientists warn that if current emission trends continue, some marine ecosystems could face irreversible damage within decades, with consequences that extend well beyond the ocean itself, including impacts on global fisheries and coastal communities that depend on them. What does the phrase "disproportionate effect" suggest in this context?

5. Ocean acidification, often described as the "other" carbon dioxide problem, occurs when the ocean absorbs excess CO2 from the atmosphere, lowering the pH of seawater. While the change in pH may seem small, it has a disproportionate effect on marine organisms that build shells or skeletons from calcium carbonate, such as corals and certain plankton species. Scientists warn that if current emission trends continue, some marine ecosystems could face irreversible damage within decades, with consequences that extend well beyond the ocean itself, including impacts on global fisheries and coastal communities that depend on them. What broader consequence does the passage mention beyond marine ecosystems?

6. Experimental archaeology involves recreating past technologies and processes—such as flint-knapping, pottery firing, or ancient construction techniques—in order to better understand how they were originally carried out. Rather than relying solely on the interpretation of artifacts, researchers physically attempt the tasks themselves, often uncovering practical constraints that would not be apparent from analysis alone. This approach has proven particularly valuable in cases where written records are absent or incomplete, offering insights into the labour, skill, and time investment required by ancient societies, and occasionally challenging long-held assumptions about how certain structures or objects were actually made. What is experimental archaeology primarily concerned with?

7. Experimental archaeology involves recreating past technologies and processes—such as flint-knapping, pottery firing, or ancient construction techniques—in order to better understand how they were originally carried out. Rather than relying solely on the interpretation of artifacts, researchers physically attempt the tasks themselves, often uncovering practical constraints that would not be apparent from analysis alone. This approach has proven particularly valuable in cases where written records are absent or incomplete, offering insights into the labour, skill, and time investment required by ancient societies, and occasionally challenging long-held assumptions about how certain structures or objects were actually made. According to the passage, why do researchers physically attempt ancient tasks?

8. Experimental archaeology involves recreating past technologies and processes—such as flint-knapping, pottery firing, or ancient construction techniques—in order to better understand how they were originally carried out. Rather than relying solely on the interpretation of artifacts, researchers physically attempt the tasks themselves, often uncovering practical constraints that would not be apparent from analysis alone. This approach has proven particularly valuable in cases where written records are absent or incomplete, offering insights into the labour, skill, and time investment required by ancient societies, and occasionally challenging long-held assumptions about how certain structures or objects were actually made. In what situation is experimental archaeology described as particularly valuable?

9. Experimental archaeology involves recreating past technologies and processes—such as flint-knapping, pottery firing, or ancient construction techniques—in order to better understand how they were originally carried out. Rather than relying solely on the interpretation of artifacts, researchers physically attempt the tasks themselves, often uncovering practical constraints that would not be apparent from analysis alone. This approach has proven particularly valuable in cases where written records are absent or incomplete, offering insights into the labour, skill, and time investment required by ancient societies, and occasionally challenging long-held assumptions about how certain structures or objects were actually made. What can experimental archaeology reveal about ancient societies, according to the passage?

10. Experimental archaeology involves recreating past technologies and processes—such as flint-knapping, pottery firing, or ancient construction techniques—in order to better understand how they were originally carried out. Rather than relying solely on the interpretation of artifacts, researchers physically attempt the tasks themselves, often uncovering practical constraints that would not be apparent from analysis alone. This approach has proven particularly valuable in cases where written records are absent or incomplete, offering insights into the labour, skill, and time investment required by ancient societies, and occasionally challenging long-held assumptions about how certain structures or objects were actually made. What does the passage suggest experimental archaeology can sometimes do to existing theories?

11. The so-called "attention economy" refers to a system in which human attention is treated as a scarce, valuable resource, competed for by an ever-expanding number of media platforms, advertisers, and content creators. Critics argue that many digital platforms are deliberately designed to maximise user engagement, sometimes at the expense of users' wellbeing, using techniques such as infinite scrolling and algorithmically curated content to sustain attention for as long as possible. Proponents, meanwhile, contend that these same tools have democratised access to information and provided unprecedented opportunities for individuals and small businesses to reach global audiences that would have been previously inaccessible. What does the "attention economy" refer to, according to the passage?

12. The so-called "attention economy" refers to a system in which human attention is treated as a scarce, valuable resource, competed for by an ever-expanding number of media platforms, advertisers, and content creators. Critics argue that many digital platforms are deliberately designed to maximise user engagement, sometimes at the expense of users' wellbeing, using techniques such as infinite scrolling and algorithmically curated content to sustain attention for as long as possible. Proponents, meanwhile, contend that these same tools have democratised access to information and provided unprecedented opportunities for individuals and small businesses to reach global audiences that would have been previously inaccessible. What do critics argue about many digital platforms?

13. The so-called "attention economy" refers to a system in which human attention is treated as a scarce, valuable resource, competed for by an ever-expanding number of media platforms, advertisers, and content creators. Critics argue that many digital platforms are deliberately designed to maximise user engagement, sometimes at the expense of users' wellbeing, using techniques such as infinite scrolling and algorithmically curated content to sustain attention for as long as possible. Proponents, meanwhile, contend that these same tools have democratised access to information and provided unprecedented opportunities for individuals and small businesses to reach global audiences that would have been previously inaccessible. What techniques are mentioned as examples of engagement-maximising design?

14. The so-called "attention economy" refers to a system in which human attention is treated as a scarce, valuable resource, competed for by an ever-expanding number of media platforms, advertisers, and content creators. Critics argue that many digital platforms are deliberately designed to maximise user engagement, sometimes at the expense of users' wellbeing, using techniques such as infinite scrolling and algorithmically curated content to sustain attention for as long as possible. Proponents, meanwhile, contend that these same tools have democratised access to information and provided unprecedented opportunities for individuals and small businesses to reach global audiences that would have been previously inaccessible. What do proponents of these platforms argue, according to the passage?

15. The so-called "attention economy" refers to a system in which human attention is treated as a scarce, valuable resource, competed for by an ever-expanding number of media platforms, advertisers, and content creators. Critics argue that many digital platforms are deliberately designed to maximise user engagement, sometimes at the expense of users' wellbeing, using techniques such as infinite scrolling and algorithmically curated content to sustain attention for as long as possible. Proponents, meanwhile, contend that these same tools have democratised access to information and provided unprecedented opportunities for individuals and small businesses to reach global audiences that would have been previously inaccessible. What is the overall structure of this passage?

16. Urban heat islands refer to metropolitan areas that experience significantly higher temperatures than their surrounding rural regions, primarily due to human activities and the prevalence of heat-absorbing surfaces such as asphalt and concrete. Unlike natural landscapes, which reflect and dissipate heat more efficiently, cities often retain heat well into the evening, exacerbating discomfort and increasing energy demand for cooling. Urban planners have proposed several mitigation strategies, including increasing green space, using reflective building materials, and incorporating vegetation into rooftops and walls, though implementation is frequently constrained by cost and competing demands on limited urban space. What is an urban heat island, according to the passage?

17. Urban heat islands refer to metropolitan areas that experience significantly higher temperatures than their surrounding rural regions, primarily due to human activities and the prevalence of heat-absorbing surfaces such as asphalt and concrete. Unlike natural landscapes, which reflect and dissipate heat more efficiently, cities often retain heat well into the evening, exacerbating discomfort and increasing energy demand for cooling. Urban planners have proposed several mitigation strategies, including increasing green space, using reflective building materials, and incorporating vegetation into rooftops and walls, though implementation is frequently constrained by cost and competing demands on limited urban space. What is given as the primary cause of urban heat islands?

18. Urban heat islands refer to metropolitan areas that experience significantly higher temperatures than their surrounding rural regions, primarily due to human activities and the prevalence of heat-absorbing surfaces such as asphalt and concrete. Unlike natural landscapes, which reflect and dissipate heat more efficiently, cities often retain heat well into the evening, exacerbating discomfort and increasing energy demand for cooling. Urban planners have proposed several mitigation strategies, including increasing green space, using reflective building materials, and incorporating vegetation into rooftops and walls, though implementation is frequently constrained by cost and competing demands on limited urban space. According to the passage, when do cities often retain heat?

19. Urban heat islands refer to metropolitan areas that experience significantly higher temperatures than their surrounding rural regions, primarily due to human activities and the prevalence of heat-absorbing surfaces such as asphalt and concrete. Unlike natural landscapes, which reflect and dissipate heat more efficiently, cities often retain heat well into the evening, exacerbating discomfort and increasing energy demand for cooling. Urban planners have proposed several mitigation strategies, including increasing green space, using reflective building materials, and incorporating vegetation into rooftops and walls, though implementation is frequently constrained by cost and competing demands on limited urban space. Which mitigation strategy is NOT mentioned in the passage?

20. Urban heat islands refer to metropolitan areas that experience significantly higher temperatures than their surrounding rural regions, primarily due to human activities and the prevalence of heat-absorbing surfaces such as asphalt and concrete. Unlike natural landscapes, which reflect and dissipate heat more efficiently, cities often retain heat well into the evening, exacerbating discomfort and increasing energy demand for cooling. Urban planners have proposed several mitigation strategies, including increasing green space, using reflective building materials, and incorporating vegetation into rooftops and walls, though implementation is frequently constrained by cost and competing demands on limited urban space. What does the passage say frequently limits the implementation of these strategies?