Babbage: Put to the test

A shortage of covid-19 tests around the world has hampered efforts to contain it. Could "pool sampling" be a solution? Also, the promise of million-mile electric car batteries? And, Magdalena Zernicka-Goetz, a developmental biologist at the University of Cambridge and Caltech, on the mysteries of life after conception. Kenneth Cukier hosts  Please subscribe to The Economist for full access to print, digital and audio
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