生态系统中多条食物链交错形成的网状结构称为______。
参考答案:食物网
_______ his being late again , he lost his job and had to stay at home.
A.Owe to
B.As result of
C.In case of
D.Because of
如图所示的电路中,闭合开关S,灯泡L1和L2均正常发光,由于某种原因灯泡L2灯丝突然烧断,其余用电器均不会损坏,则下列结论正确的是( )
A.电流表读数变大,电压表读数变小
B.灯泡L1变亮
C.电源的输出功率可能变大
D.电容器C上电荷量增大