人类在生物圈中扮演的角色是（　　）

如图是一滴血在显微镜视野中的示意图．已知正常人红细胞的含量为（4.0﹣5.5）×10¹²个/L，白细胞为（4﹣10）×10⁹个/L，白细胞个体一般较红细胞大．请根据图回答问题．

（1）视野中数量最多的血细胞是____ ____ ．某人经常精神不济，容易疲劳，经血液化验，此人红细胞数目为3×10¹²个/L．据此判断此人患有____ 症．这种病人应多吃一些含____ 和____ 丰富的食物．

（2）人体某处受伤感染时，____ ____会穿过毛细血管壁，聚集在感染处，吞噬病菌．具有运输养料和废物功能的是____ ；能够携带氧的是红细胞中的____ ．

（3）受伤流血时，伤口处血液很快凝固止血了，起作用的血细胞是____ ____ ．

    Most people sleep at night, but Frank sleeps during (在……期间) the day and works at night. His work is to guard（守卫） a big ____. Frank likes his work. He knows that it is ____ to guard the building at night. If he hears any noise, he goes ____ to see what it is. Most of the time he walks around inside the big building, but he also walks around outside. When he is ____ he can sit on a chair by the door (门). It is very cold in winter. He always ____ a warm coat when he is working.

    Frank used to feel lonely (过去感到孤独) because no one ____ with him in the evening. One night when Frank was walking outside, he ____ a noise. He went very quietly to the noise to see if someone was there, ____ he only saw a small dog. Frank talked to the dog. It ____ cold. He took the dog inside the building, and the dog followed ____ around happily.

    Now Frank is not lonely. The dog is his good friend.