TOEFL iBT VIP Practice Exam

Read the following passage and answer the question below. "The phenomenon of ocean acidification has emerged as one of the most pressing environmental concerns of the 21st century. As atmospheric carbon dioxide concentrations increase due to fossil fuel combustion and deforestation, approximately 30% of this CO₂ is absorbed by the world's oceans. This absorption triggers a series of chemical reactions that lower the pH of seawater, rendering it more acidic. Since the Industrial Revolution, average ocean pH has dropped from 8.2 to 8.1 — a seemingly minor shift that nonetheless represents a 26% increase in ocean acidity, owing to the logarithmic nature of the pH scale. Marine organisms that rely on calcium carbonate to construct shells and skeletons — including oysters, clams, sea urchins, and certain species of phytoplankton — face existential threats as increasingly acidic conditions dissolve or weaken these structures. The cascading effects extend throughout marine food webs, potentially disrupting fisheries that billions of people depend on for protein. Some researchers argue that certain species may adapt over time through natural selection, but the pace of contemporary acidification far exceeds that of any previous acidification event in the geological record, leaving little confidence that adaptation can keep pace with change." The word "rendering" as used in the passage is closest in meaning to which of the following?

Questions 2–30 and full explanations are VIP-exclusive.