问题 选择题

幼体用鳃呼吸,而成体用肺兼皮肤呼吸的动物是(  )

A.家鸽

B.青蛙

C.鲸

D.蜗牛

答案

青蛙的幼体生活在水中,用鳃呼吸,用鳍游泳,心脏一心房一心室;成体生活在陆地上,也能生活在山上水中,用肺呼吸,皮肤裸露,辅助呼吸,四肢游泳或跳跃,心脏二心房一心室.幼体和成体的差别较大,属于变态发育;家鸽的气囊辅助肺进行双重呼吸;鲸是哺乳动物,幼体与成体的呼吸器官是都肺;蜗牛外套膜腔会在壳口处形成1个开口,称为呼吸孔,这是气体进出的地方.

故选:B

多项选择题
单项选择题

Anthropology is the study of human beings as creatures of society. It (1) its attention upon those. physical characteristics and industrial techniques, those conventions and values, which (2) one community from all others that belong to a different tradition.

The distinguishing mark of anthropology among the social sciences is that it includes for serious study other societies (3) our own. For its purposes any social (4) of mating and reproduction is as significant as our own. To the anthropologist our customs and those of a New Guinea tribe are two possible social schemes for (5) a common problem, and in so far as he remains an anthropologist he is (6) to avoid any weighting of one (7) the other. He is interested in human behavior, not as it is shaped by one tradition, our own, but as it has been shaped by any tradition (8) He is interested in a wide (9) of custom that is found in various cultures, and his object is to understand the way in which these cultures change and (10) , the different forms through which they express themselves and the (11) in which the customs of any peoples function in the lives of the (12) .

Now custom has not been commonly regarded as a (13) of any great moment. The inner workings of our own brains we feel to be uniquely (14) of investigation, but custom, we have a way of thinking, is behavior at its most commonplace. (15) , it is the other way round. Traditional custom is a mass of detailed behavior more astonishing than (16) any one person can ever evolve in individual actions. Yet that is a rather (17) aspect of the matter. The fact (18) first rate importance is the predominant role that custom (19) in experience and belief, and the very great varieties it may (20)

3()

A.of

B.from

C.for

D.than