题干
阅读下面材料，在空白处填入适当的内容或括号内单词的正确形式。
Over time, many flowering plants and ____ (they) animal pollinators(传粉昆虫) have evolved together. The plant needs the animal to pollinate it and the animal ____ (reward) with food called nectar when it visits the flowers. Pollen becomes ____ (attach) to the animal during its visit to a flower____ is then passed on to another plant's blossom on its next visit. So pollination takes place, therefore ____ (increase) the chances of the survival of the plant species.
The type of pollinator ____ (depend) on the characteristics of the flower such ____ its colour, shape, size and smell. For example, yellow flowers attract bees, while red flowers attract ____ (butterfly). The nectar in some flowers can only be reached by a bird ____ a long bill or a long-tongued moth or butterfly. Flowers that attract bees often have a special way ____ (guide) the bees to the nectar inside.
