Kruskal's and Prim's algorithms are two approaches for finding the minimum spanning tree (MST) of a connected, undirected graph. Kruskal's algorithm builds the MST by adding edges one by one, always choosing the lowest weight edge that avoids cycles. Prim's algorithm grows the MST from a starting vertex by always adding the lowest weight edge connected to the growing tree. Both use greedy approaches. The time complexity of Prim's is O((V+E)log(V)) and Kruskal's is O(Elog(V)) due to sorting edge weights. MSTs have applications in network design, image processing, and social network analysis.