Routing protocols use different techniques for assigning ______ to individual networks. Further, each routing protocol forms a metric aggregation in a different way. Most routing protocols can use multiple paths if the paths have an equal ______ . Some routing protocols can even use multiple paths when paths have an unequal cost. In either case, load ______ can improve overall allocation of network bandwidth. When multiple paths are used, there are several ways to distribute the packets. The two most common mechanisms are per-packet load balancing and per-destination load balancing. Per-packet load balancing distributes the ______ across the possible routes in a manner proportional to the route metrics. Per-destination load balancing distributes packets across the possible routes based on ______.

A. bandwidthsB. sources C. destinations D. delays

2006年8月24日，根据国际天文学联合会大会投票5号决议，冥王星被排除在行星行列之外，正式从九大行星中除名，而将其列入“矮行星”。冥王星的发现当时是根据（）

A.哥白尼日心说的推算

B.牛顿力学的推算

C.法拉第定律的推算

D.爱因斯坦的相对论