ISAT - International Student Admissions Test International Student Admissions Reading Comprehension: Main Idea 1 — Questions and Answers
Question 1: A passage explains that the Great Barrier Reef, the world's largest coral reef system, is threatened by rising ocean temperatures, which cause coral bleaching events that have damaged over 50% of its coral since 1980. Conservation efforts include reducing carbon emissions and establishing marine protected zones. What is the main idea?
- Rising ocean temperatures are caused by human industrial activity
- The Great Barrier Reef is being severely damaged by warming oceans, prompting conservation responses (Correct answer)
- Marine protected zones are the most effective conservation strategy
- Coral bleaching affects only the Great Barrier Reef and no other reef systems
Correct answer: The Great Barrier Reef is being severely damaged by warming oceans, prompting conservation responses
The passage centers on the threat warming oceans pose to the Great Barrier Reef and the conservation measures being taken in response—this is the unifying idea that connects all the details provided.
Question 2: A passage describes how migratory birds navigate thousands of kilometers using a combination of Earth's magnetic field, star patterns, and memorized landmarks. Research shows that even young birds raised in isolation can orient themselves correctly without prior experience. What is the main idea?
- Birds memorize landmarks during their first migration to guide future journeys
- Migratory birds possess multiple sophisticated, partly innate navigation systems (Correct answer)
- Earth's magnetic field is stronger in regions where birds migrate most frequently
- Isolated birds cannot navigate as accurately as those raised in flocks
Correct answer: Migratory birds possess multiple sophisticated, partly innate navigation systems
The passage highlights that birds use several navigational tools—magnetic fields, stars, and landmarks—and that some of this ability is innate, making the sophistication and multiplicity of their navigation the central point.
Question 3: A passage discusses how the Black Death, which swept Europe between 1347 and 1351, killed roughly one-third of the continent's population. The resulting labor shortage gave surviving peasants new economic leverage, accelerating the decline of feudalism and reshaping European social structures. What is the main idea?
- The Black Death was caused by fleas carried on rats travelling along trade routes
- European medical practices in the 14th century were ineffective against plague
- The Black Death's massive death toll triggered lasting social and economic transformation in Europe (Correct answer)
- Feudal lords responded to the Black Death by granting peasants more land
Correct answer: The Black Death's massive death toll triggered lasting social and economic transformation in Europe
The passage moves from the plague's death toll to its broader consequence—the reshaping of feudal society—making the long-term social and economic impact the central idea rather than any single cause or response.
Question 4: A passage explains that sleep serves critical restorative functions: during deep sleep the brain flushes out metabolic waste via the glymphatic system, consolidates memories, and repairs cellular damage. Chronic sleep deprivation is linked to elevated risks of Alzheimer's disease, cardiovascular conditions, and impaired immune response. What is the main idea?
- The glymphatic system only activates during the deepest stage of sleep
- Adequate sleep is biologically essential because it performs vital restorative functions for the brain and body (Correct answer)
- Cardiovascular disease is the most serious consequence of sleep deprivation
- Memory consolidation requires at least eight hours of uninterrupted sleep
Correct answer: Adequate sleep is biologically essential because it performs vital restorative functions for the brain and body
The passage presents multiple restorative processes that occur during sleep and connects their absence to serious health risks, making the biological necessity of sleep the unifying main idea.
Question 5: A passage describes how Japanese bullet trains, known as Shinkansen, achieve speeds exceeding 300 km/h by combining aerodynamic design, dedicated tracks free of road crossings, and computerized safety systems. Since their 1964 debut, the network has carried over ten billion passengers with zero passenger fatalities. What is the main idea?
- Japan's Shinkansen network demonstrates that high-speed rail can be both fast and exceptionally safe (Correct answer)
- The aerodynamic nose design of Shinkansen trains was inspired by the kingfisher bird
- Dedicated tracks are the single most important factor in bullet train safety
- Japan built the first high-speed rail network in the world in 1964
Correct answer: Japan's Shinkansen network demonstrates that high-speed rail can be both fast and exceptionally safe
The passage brings together speed, engineering design, and the safety record to make the point that the Shinkansen is a model of combining high performance with safety—this is its central argument.
Question 6: A passage explains that urban heat islands form when natural vegetation is replaced by concrete and asphalt, which absorb and retain solar energy, raising city temperatures by up to 7°C compared with surrounding rural areas. This effect increases energy demand for cooling, worsens air quality, and disproportionately harms low-income neighborhoods with less green space. What is the main idea?
- Low-income neighborhoods have fewer trees because of historical zoning decisions
- Urban heat islands are temperature differences caused by city surfaces and carry wide-ranging harmful consequences (Correct answer)
- Air conditioning is the primary driver of increased energy consumption in cities
- Planting trees is the only effective solution to the urban heat island effect
Correct answer: Urban heat islands are temperature differences caused by city surfaces and carry wide-ranging harmful consequences
The passage defines the urban heat island phenomenon and traces its multiple negative consequences, making the cause-and-effect relationship between built surfaces and broad urban harm the central idea.
ISAT - International Student Admissions Test International Student Admissions Reading Comprehension: Main Idea 1
A passage explains that the Great Barrier Reef, the world's largest coral reef system, is threatened by rising ocean temperatures, which cause coral bleaching events that have damaged over 50% of its coral since 1980.
Conservation efforts include reducing carbon emissions and establishing marine protected zones.
What is the main idea?