稳态机制
参考答案：
是指内部组织和结构的一种调节功能，即调节能量流动和物质循环的能力，调节生态系统中各种成分之间的营养关系的能力。
If I had taken part in the 400-meter relay race in the sports-meet, our class _____ the race．I’m _____ weight this year．
A．might not have won; gaining
B．Would not have beaten; putting on
C．can not have defeated; losing
D．must not have achieved; acquiring
下列不属于合同担保的形式的是( )。
A．预付款 B．保证 C．定金 D．质押
