[简答题]What, then, does Drucker suggest are the new knowledge-based industries on which economic growth will depend He discusses three categories of such industries. The first of these is the information industry. This industry collects, stores, spreads, and applies knowledge. It depends on the computer. In the future, however, the computer itself will probably become less important than communicating and applying knowledge. Drucker foresees a central computer that will make information available to everyone. Another source of new industries is the science of the oceans. New technologies may help to supply food and minerals from the seas. A third new source of economic growth is the materials industry. This industry provides the materials for making objects. one such industry that has already become economically important is the plastic industry. Drncker explains that throughout history our traditional materials have been metals, glass, natural fibers, and paper. Today, with the help of modem