"If G has a walk that uses all the edges, then G is connected." I know that this statement is false but how can I prove that it is false?

12. Draw diagrams for grid graphs Gm,n that is D(Gm,n) for all Gm,n with m≤7 and n ≤ 7 including D(Go,o) and D(G7,7). How many components has a link D(Gm.n) for each case with m, n as before? (History) Write a very short biographical sketch (half a page) of: Archimedes (287 BC-212 BC), Isaac Newton (1643-1727), Gottfried Wilhelm Leibniz (1646-1717), Leonhard Euler (1707-1783), Johann Carl Friedrich Gauss (1777 - 1855); Grigori Yakovlevich Perelman (1966-),

Compute the betweenness centrality of all four vertices

If u and v are vertices of a connected graph G, then d(u, v) is the length of a shortest path in G joining u and v. We call d(u, v) the distance from u to vShow that for any three vertices d(u, v) + d(v, w ) > = d(u, w)