Question

Why did Austria-Hungary annex Bosnia and Herzegovina?

to create a larger divide between France and Russia
to take advantage of trade routes on the Adriatic Sea
to prevent Russia from taking Ottoman Empire territory
to seize territory from the declining Ottoman Empire

Answer 1

to seize territory from the declining Ottoman Empire

(Austria-Hungary formally annexed Bosnia and Herzegovina—territories the empire had already occupied and administered since 1878—to expand its power as Ottoman control in the Balkans weakened and to block Serbian and Russian influence in the region.)