It is not true that Prussia only acquired those provinces from Denmark and France in the period 1864-1871. Much more significantly, Prussia also absorbed much of the rest of Germany when Bismarck created the German Empire.
Correct. Pat also fails to mention that the Austro-Prussian War war removed Prussia’s only rival for dominance in Germany. Those 3 wars were carefully planned strategically to create a new Empire dominated by Prussia. French desire to avenge defeat in the Franco-Prussian War was a major cause of WW I. Outnumbered by the Germans, they allied themselves with Russia, thereby surrounding Germany. I consider the Russians the biggest villains because their giant, rotten, corrupt Empire had no legitimate reason to meddle in civilized Europe.