题目

At present, in many American cities especially, many teachers in the public schools say they are underpaid. They point to jobs such as secretary or truck driver, which often pay more to start than that of a teacher. In many other fields, such as law, medicine, computer science, a beginning worker may make more than a teacher who has taught for several years.          Teaching has never been a profession that attracted people interested in high salaries. It is by history a profession that has provided rewards in addition to money—the satisfaction of sharing knowledge, of influencing o关于“被子植物”繁殖后代的过程，描述正确的是（　　）A．开花后必须经过传粉和受精过程，才能形成果实B．所有植物的传粉过程都需要有动物的帮助C．胚是新植物的幼体，是由雌蕊的胚珠发育而成的D．开花结果与真菌的繁殖过程一样，属于有性生殖