GMAT Verbal 32: Detail Questions — Answering From the Line

Until the 1960s, the Aral Sea, which lies between Kazakhstan and Uzbekistan, was the fourth-largest lake in the world. It was fed by two great rivers, the Amu Darya and the Syr Darya. Then Soviet planners, seeking to turn the surrounding desert into cotton fields, diverted much of the rivers' water into irrigation canals. The sea began to shrink, and the shrinking accelerated. By the 2000s it had split into separate bodies of water and had lost most of its former area.

The consequences reached far beyond the shoreline. As the water retreated, the fishing industry that had employed tens of thousands of people collapsed, and former ports were left many kilometres from the water. The exposed seabed became a new desert, now called the Aralkum, from which winds carry dust laden with salt and agricultural chemicals across the region.

The story has not been one of loss alone. In 2005 Kazakhstan, with support from the World Bank, completed the Kok-Aral dam, which holds the water of the Syr Darya in the northern part of the sea. The North Aral's level rose, its water became less salty, and fish catches recovered enough to revive some local fishing. The much larger southern part, which depends on the heavily used Amu Darya, has continued to shrink. The contrast suggests that the sea's decline was not irreversible everywhere — but also that recovery depends on how much water people are prepared to leave in the rivers.

The discovery of penicillin is often told as the story of a lucky accident, and it began as one. In 1928 the Scottish bacteriologist Alexander Fleming noticed that a mould growing on one of his culture plates had killed the bacteria around it. He named the active substance penicillin and published his findings, but he was unable to purify it in useful amounts, and for about a decade it attracted little attention.

The work that turned the observation into a medicine was done at Oxford, where Howard Florey and Ernst Chain led a team that, from 1939, developed methods to extract and purify penicillin and tested it, first in mice and then in patients. Their first patient, a policeman treated in 1941, improved dramatically, but the supply of the drug ran out and he died. The question was no longer whether penicillin worked but how to make enough of it.

That problem was solved largely in the United States, where government laboratories and drug companies developed methods to grow the mould in large tanks. By 1944 production had risen to levels that allowed penicillin to be supplied widely to Allied forces. In 1945 Fleming, Florey and Chain shared the Nobel Prize in Physiology or Medicine — a recognition that the discovery had required not one accident but years of deliberate work by many people.