Simon Kuznets identified medium-term economic cycles lasting 15 to 25 years, which are primarily driven by demographic shifts and massive investments in ___ and housing infrastructure.

Answer: construction (or real estate / infrastructure)

Kuznets swings are closely tied to population growth, migration patterns, and the lifespan of physical infrastructure. When a generation enters its prime household-forming years, it triggers a massive, multi-decade boom in residential construction and related infrastructure, which eventually peaks, saturates, and enters a long period of decline before the next demographic wave begins.