抵抗力
参考答案：它是生态系统抵抗外部干扰、维持系统结构原状的能力。
Everyone was silent as the organizer ________ the result of the speech competition.
A．announced
B．pronounced
C．arranged
D．instructed
运动心理学侧重研究体育教育教学中的心理现象。
