[2026] PTE Academic Reading - Multiple Choice, Single Answer

The Great Oxygenation Event, occurring roughly 2.4 billion years ago, is often celebrated as the pivotal moment that paved the way for complex multicellular life. However, to the anaerobic organisms that dominated the early Earth, the sudden rise of atmospheric oxygen was not a gift, but a lethal pollutant. This transition represents perhaps the most significant mass extinction in planetary history, as the reactive nature of oxygen destroyed the delicate cellular structures of primitive life forms. Modern narratives frequently overlook this carnage, framing the rise of oxygen as a teleological step toward human existence rather than a chaotic environmental catastrophe. Scientists must resist the temptation to view evolutionary history as a linear progression with humanity as its intended climax. By decoupling the biological necessity of oxygen from its destructive origins, we gain a more profound, if less comforting, understanding of how life survives on a volatile planet.