ISAT - International Student Admissions Test International Student Admissions Reading Comprehension: Main Idea 1

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?

Accepted Answer

The Great Barrier Reef is being severely damaged by warming oceans, prompting conservation responses

Answer

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?

Accepted Answer

Migratory birds possess multiple sophisticated, partly innate navigation systems

Answer

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?

Accepted Answer

The Black Death's massive death toll triggered lasting social and economic transformation in Europe

Answer

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?

Accepted Answer

Adequate sleep is biologically essential because it performs vital restorative functions for the brain and body

Answer

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?

Accepted Answer

Japan's Shinkansen network demonstrates that high-speed rail can be both fast and exceptionally safe

Answer

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.

ISAT - International Student Admissions Test Practice Test

ISAT - International Student Admissions Test Practice Test

ISAT - International Student Admissions Test International Student Admissions Reading Comprehension: Main Idea 1