______ the cold, thin air and low oxygen levels also can cause mountain sickness.

A．On behalf of

B．Apart from

C．In terms of

D．Except for

苗床发生烟草猝倒病后，如果苗床潮湿，在病苗四周的床土上可见一层黑色絮状物。染病幼苗往往全部死亡，在苗床形成块状的“圆补丁”，致使苗床严重缺苗