有害需求是指市场上的某些产品或服务对消费者的身心健康无益甚至有害的需求。例如:食品和化妆品中包含了过量的某种对人体有害的物质; 不安全的电器;假药以及有害公众利益的赌具、毒品、黄色书刊和音像等。针对这种情况,营销的任务就是抵制和消除这种需求。企业要通过自己的宣传,指出该种产品及需求的危害性，帮助消费者辨别真伪、判断是非,促使他们主动放弃对这类产品和服务的需求,以维护消费者和社会公众的利益。
因此，快速识别事物是有益还是有害的需求可能对摇滚艺术产生了巨大的影响，并解释了为什么一些形象在不同文化中比其他的更常见。
So the need to quickly recognise things that could be helpful or harmful could have had a great influence on rock art and explain why some images are more common across cultures than others.
实践证明，低耕农业提高了作物产量，减少了用水量；而且，由于有害植物变少了，这种农业对化工产品的需求也降低了。
It has been proved that Low Till Farming increases harvests and reduces water use, and this method reduced the need for chemical products because there are fewer unwanted plants.
看电视不一定是有害的，但必须适度，要平衡孩子的其他需求，让孩子健康成长。
TV is not necessarily toxic, but is something that has to be done in moderation; something that balances the other needs of the child for healthy development.
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