下列各项是动物在自然界中的作用[]A．在维持生态平衡中起着重要的作用B．能促进生态系统中的物质循环C．能帮助植物传粉，传播种子D．以上都是-八年级生物

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• 动物作为生态系统中的消费者，其与物质循环有关的主要功能是[]A．动物可以帮助植物传粉和传播种子B．动物在食物链和食物网中与植物相互依赖、相互制约C．进入动物体的食物将被分-八年级生物
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• 动物对于一个生态系统来说是很重要的，这是因为[]A．动物是食物的唯一来源B．动物能促进生态系统的物质循环C．动物能固定二氧化碳D．动物能释放氧气-八年级生物
• 大量捕杀农田中的青蛙会造成什么样的后果[]A．蛇类的食物断绝B．农田作物减产C．植食性昆虫减少D．农田温度升高-八年级生物
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• (2014·福建省普通高中质量检查)Because of H7N9 bird flu，all the chicken markets in Shanghai have been closed and
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