What did the interior city of great zimbabwe become known for?
wars
stone architecture
diamonds
irrigation systems

The correct answer is B) stone architecture.

The interior city of Great Zimbabwe became known for its stone architecture.

Between the 11th and 15th centuries, Great Zimbabwe was one of the most dominant cultures in Africa. One of its most important legacies was architecture. They were capable of building great stone walls that surrounded the city in Masvingo. Their architectonic knowledge was impressive because they built the gigantic structures without using mortar. They relied on perfect masonry to place the stone and form the walls in an architecture technique called "dry stone walling." If you visit the place you can admire many relics of the original buildings.

to act quickly in times of danger to the united states

because you have to act quickly if you want to live/survive.