Explanation of minimal spanning tree

The table below shows the order in which nodes are added to the minimal spanning tree rooted at node 0. In each iteration, a new node is added to the tree, and the distance to that node from all nodes adjacent to it are updated. Refresh the page to see another randomly generated unweighted graph.

0123456789
0infinfinfinfinfinfinfinfinf
0inf1infinfinf14infinfinf
081inf11inf1412infinf
081611inf212infinf
081611inf212infinf
0816117210infinf
08163721013inf
081637210136
081637210136
081637210136