GRE General Test Practice Questions - Graduate Record Examinations General Test Exam

Read the passage and answer the question. "Urban heat islands—metropolitan areas significantly warmer than surrounding rural zones—arise primarily from the replacement of vegetation with heat-absorbing impervious surfaces such as asphalt and concrete. Secondary contributors include waste heat from vehicles, air conditioners, and industrial processes. The effect is not merely uncomfortable: elevated urban temperatures increase electricity demand, worsen air quality via accelerated ozone formation, and disproportionately harm low-income communities that lack access to air conditioning. Mitigation strategies include green roofs, urban tree canopies, and cool pavements that reflect rather than absorb solar radiation." According to the passage, which of the following is cited as a PRIMARY cause of urban heat islands?