春天鲜花盛开的时候，花丛中飞舞着蜜蜂等许多昆虫。你认为它们对花朵起的主要作用是[]A．修饰花朵B．防治害虫C．帮助传粉D．传播种子-八年级生物

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• 白蚁的消化道内生活着一种叫鞭毛虫的单细胞生物，它能把白蚁所食的木纤维分解成营养成分，供白蚁吸收，同时白蚁为鞭毛虫的生活提供有机物。白蚁和鞭毛虫的关系是[]A．腐生B．竞-八年级生物
• 用细菌和真菌作为生物杀虫剂治虫，可减少农药的用量，减轻对环境的污染，这种方法也属于生物防治。下列不属于生物防治的是[]A．苏云金杆菌杀棉铃虫B．用粘蝇纸毒杀苍蝇C．白僵菌-八年级生物
• 鼠兔是青藏高原上广泛分布的一种小型无尾的兔类，在许多人眼里认为它和家畜争夺草场，导致高山草地退化。因此，鼠兔一直被人类所毒杀。其实，鼠兔是青藏高原生态系统的关键性-八年级生物
• 下列哪一项不属于生物防治[]A．以农药治虫B．以虫治虫C．以鸟治虫D．以菌治虫-八年级生物
• 下图为家蚕发育过程示意图，请据图回答下列问题（1）A、B分别表示雄蛾和雌蛾，C表示______阶段，E表示_____阶段。像这样的发育过程称为发育。（2）养蚕是为了获得蚕丝，要使蚕丝-八年级生物
• 在自然界中，供给植物光合作用所需二氧化碳的过程有[]A．植物将自身合成的有机物分解B．动物将摄取的有机物分解C．微生物将动植物遗体分解D．以上三者都包括-八年级生物
• 我国的海洋鱼类资源非常丰富，为了充分利用海洋鱼类资源，应该多捕鱼。[]-八年级生物
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• 如图所示，在一个叫大的玻璃缸中，下层装入颜色较深的黏土，第二层装入颜色较浅的的沙土，上层装入颜色较深的黏土。每层都稍加按压，玻璃缸中的土要保持一定的湿度。选几条生-八年级生物
• 丸花蜂在取食花蜜时，也帮植物传了粉，这说明动物与植物关系是[]A．动物必须依靠植物生存B．丸花蜂是寄生虫C．动物和植物互为敌D．动物和植物相互适应、相互依存-八年级生物
• 动物在自然界中有哪些作用，请分别从生态平衡、物质循环和与其他生物的关系等方面说明，并各举一例。-八年级生物
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• 蚯蚓是人类的好朋友，它不但可以疏松土壤，还可以：[]A．是常见的中药材B．处理垃圾C．增加土壤的肥性D．前三项都对-八年级生物
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