Multicast is being deployed in the network， and only ip pim sparse-dense mode has been configured on all interfaces in the network to support a new video streaming application. No other multicast configuration was applied anywhere in the network. Since enabling multicast， the network monitoring tools show periodic spikes in link utilization throughout the network， even in areas where the video application is not being used. What could be a possible cause？（） ["PIM sparse mode is being used.","PIM dense mode is being used.","The BGP multicast address family has not been configured.","IGMP version 3 is being used.","IP PIM neighbor filters have not been applied."]
重要焊缝是指直接涉及到人身安全的焊缝，如（） ["乘坐物支撑件焊缝、升降油缸（气缸）上下支撑件焊缝","乘坐物吊挂点支撑件焊缝","轨道对接焊缝","车辆连接器焊缝、吊厢框架焊缝等"]
阐述食物链在生态系统的能量流动中所起的作用。
中国资本主义进一步发展产生了什么影响？
《中国之旅》的作者是？（） ["田中角荣","大江健三郎","川端康成","龟井胜一郎"]
丢勒的艺术特点？
