WHEN WE LOOK at nature, it has become commonplace to see a fastidiously self-regulating system at work: wildebeest trim the savannah grasses, lions cull the wildebeest herds, and vultures clean the bones of both. Forests take in the carbon dioxide we exhale, use it to grow, and replace it with oxygen. The planet even has a thermostat, the carbon cycle, ... (Full article: 2549 words)

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