Why is the unification of germany linked to the causes of world war i?

Causes of WW1: Nationalism

Strong nationalist elements led to the re-unification of Italy in 1861 and Germany in 1871. ... Large areas of both Austria-Hungary and Serbia were home to differing nationalist groups, all of whom wanted freedom from the states in which they lived.

Explanation:

(d) rivers.

explanation:

civilizations developed around rivers because their waters provided places to hunt and fish. also, as the rivers flooded, the lands around them became fertile. this allowed them to support farming. this is especially true of the nile river, which flooded the same time each year.

in the 1800s, locomotives powered by steam made transportation faster and cheaper. the resulting rapid growth of railroads led to the connection of the atlantic and pacific railroad in oklahoma city in 1897.

in the last years of the century, the improvement of steam-based engines the expansion and growth of railroads. this growth increased when the companies started to build and expand, such as the atlantic and pacific railroad, which connected new mexico with california, and missouri with oklahoma. many of these new networks were built in oklahoma, and these changes transportation henceforward.