生态平衡是指生态系统中的各种生物（  ）

阅读材料，完成任务。

    My uncle Jack is an interesting man. When he speaks, his mustache（胡子） always dances. It is so funny. He wears glasses and a funny hat.

    I don't like my boss（老板） at all. He is heavy with two small eyes. I think his glasses are too small for him.

— Look, the salesman（商人） is coming.

— Which one?

— The one with short black hair. He always takes his umbrella(雨伞) and suitcase(旅行箱). And his tie is very ugly.

— What are you doing, Lucy? Look at your pants. They are so dirty!

— I am doing some cleaning. Don't come here, Jane. Your beautiful skirt will be dirty.

被弃耕的农田多年后将演替至顶极群落（演替所达到的最终平衡状态），其上物种甲、乙、丙的光合速率受光照强度的影响如图所示，据图回答下列问题：

地球自转和公转运动的特征相同的是（    ）

如图是菲菲在学习了“细胞分裂与分化”后归纳的玉米植物体的结构层次示意图．请据图回答下列问题．