A certain species of bird has two basic varieties, crested and noncrested. The birds, which generally live in flocks that contain only crested or only noncrested birds, tend to select mates of the same variety as themselves. However, if a bird that is raised in a flock in which all other members are crested is later moved to a mixed flock, then that bird—whether crested or noncrested—is likely to select a crested mate. This fact indicates that the birds preference for crested or noncrested mates is learned rather than genetically determined. Which one of the following, if true, provides the most support for the argument?
A. Birds of other species also tend to show preferences for mates that have one or another specific physical feature.
B. In general there are few behavioral differences between the crested and noncrested birds of the species.
C. Both the crested and noncrested birds of the species tend to select mates that are similar to themselves in size and age.
D. If a crested bird of the species is raised in captivity apart form. other birds and is later moved to a mixed flock, that bird is likely to select a crested mate.
E. If a bird of the species is raised in a flock that contains both crested and noncrested birds, that bird shows no preference for one variety or the other in its selection of a mate.
查看答案
2011年我国全年完成邮政业务总量大约为多少亿元?()
A. 1859
B. 1732
C. 1608
D. 1588
随着清明、端午等传统节日的相继到来,各地公祭之风又起,甚至出现了“伏羲东奔西走,黄帝到处安家。诸葛四处显灵,女娲遍地开花”的热闹场面,政府官办清明、端午等传统节日,对此你怎么看?
做相关研究和比较研究,最有效的样本容量是每组至少()。
A. 100
B. 15
C. 30
D. 150
工厂火灾,有数十人伤亡,由于事故原因正在调查,新闻发言人通报的信息并不是很多,很多记者提出质疑,部分家属情绪激动,并冲上台,现场秩序出现混乱,你作为新闻发布会的主持人,该怎么做?