简述温度因子的生物作用。
参考答案:
(1)节律性变温对生物有影响。尤其是极端温度对食物的生长发育存在极大的影响。
(2)温度是决定物种分布区域的主要生态因子.
Which of the following statements can best describe Texans
A.They are aggressively self-confident of their wisdom.
B.They are brutally crude in making a living for themselves.
C.They are blindly allergic to negative comments on their weakness.
D.They are openly and crudely thin-skinned about discriminations against them.
一台三相六极感应电动机接于工频电网运行,若转子绕组开路时,转子每相感应电势为110V。当电机额定运行时,转速nN=980r/min,此时转子每相电势E2s为()V。
A.1.47
B.2.2
C.38.13
D.110