Doyouwanttoknowhowan的精選

問題詳情：Doyouwanttoknowhowandwhyafallleafchangescolor?Wefirsthavetounderstandwhatleavesareandwhattheydo．Leavesaretheworld’sfoodfactories．PlantstakewaterfromthegroundthroughtheirrootsandtakeCO2fromtheai...