一个鱼池是圆形的,它的半径是10米,如果沿着鱼池的边走上一圈,要走( )米。
62.8
治疗蛲虫的方法有()
A.内服槟榔煎剂
B.内服驱虫粉
C.百部煎液灌肠
D.禁止小儿搔抓肛门
E.夜间在肛门口捉虫
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.(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.