Investigators were testing the effects of different colored walls on two groups of visitors to an exhibit of paintings.For the first group the room　 1　 (paint)white; for the second，dark brown.　 2　 　(move)of each group was followed by 　3　 　electrical system under the carpet.The experiment showed that those　 4　 　entered the dark brown room walked more quickly，covered more area，and spend 　5　 (little)time in the room than the people in the white environment.Dark brown stimulated more activity,　 6　 　the activity ended sooner.Another experiment presented three groups of subjects　 7　 　the same photographs，but each group was 　8　 a different kind of a room-an “ugly? room like a messy storeroom，an average room such as a nice office，and a nicely 　9　 (design)living room with carpeting and drapes.Results showed that the subjects in the studies suggest students do better on tests 　10　 　(take)in comfortable，attractive than in ordinary?looking or ugly rooms.

15．下图是人红细胞形态变化的图解。请结合图解回答下面的问题：

人的正常　　　　　 人的圆涨的　　　　　　 人的涨破的

红细胞　　　　　　　 红细胞　　　　　　　　　 红细胞

(1)人正常红细胞生活环境的无机盐浓度约为_____________%。

(2)人成熟的红细胞没有细胞核，应属于原核细胞还是真核细胞?　 _____________。

(3)人的红细胞在幼年时期是具有细胞核的。在发育成熟过程中，红细胞核逐渐退化，并从细胞中排出。红细胞核逐渐退化并排出的意义是_________________________________

　 ______________________________________________。

(4)上图所示的红细胞形态的变化要在什么条件下才能发生?_______________________。

(5)如果把红细胞放入浓盐水中，红细胞形态将发生怎样的变化?_____________________。

⑴0.9　 ⑵ 真核细胞 ⑶ 为携带氧气的血红蛋白腾出空间 ⑷ 蒸馏水或清水⑸失水皱缩