Final answer:
Nationalism played a significant role in the rise of Italy and Germany by fostering a sense of shared identity and heritage, which led to the unification of the nations.
Step-by-step explanation:
Nationalism played a significant role in the rise of Italy and Germany in the 19th century. In Italy, the nationalist leader Giuseppe Mazzini founded Young Italy, which advocated for the sovereignty and independence of the Italian people. This movement spread beyond Italy, with young nationalist groups emerging in Germany and Ireland. In both Italy and Germany, the sense of shared identity and heritage fostered by nationalism laid the groundwork for the unification of the nations.