星期六,妈妈接小玲玲回家。路上,玲玲看着马路两旁的树上都长出了嫩绿的叶子,就问:“妈妈,树叶为什么都是绿的?”妈妈说:在植物世界里,有三十至四十万种植物。它们分成两大类,一类是绿色植物,另一类是非绿色植物。我们常见的大多数是绿色植物。这是因为树叶里有叶绿素、胡萝卜素、叶黄素等色素。在正常情况下,叶绿素的含量最多,叶子就绿。到了秋天,由于气候的变化,叶绿素的形成少而分 Saturday, mother pick Lingling home. On the way, Ling-ling looked at the green leaves on both sides of the road and asked: “Mom, why are the leaves green?” "Mom said: In the plant world, there are 300,000 to 400,000 species of plants. They are divided into two major categories, one is green plants and the other is non-green plants. Most of us common are green plants. This is because there are chlorophyll in the leaves, carotene, lutein and other pigments. Under normal conditions, the content of chlorophyll is the most, and the leaves are green. In the fall, due to climate change, the formation of chlorophyll less points