State authorities have ordered cutbacks in deliveries of water from the delta because of the threat to endangered species such as salmon and smelt.
2
这些条件有助于进化出用于支撑枝干的结构、运输水分和养分到植物各部分的导管以及储存水分的结构。
These conditions favored the evolution of the structures that support the body, vessels that transport water and nutrients to all parts of plant, and structures that conserve water.