Question

what were built in europe to connect rivers for economic and transportation purposes. fjords polders canals rewatch

Explanation:

Fjords are long, narrow inlets with steep sides or cliffs, typically formed by glacial erosion. Polders are low - lying tracts of land reclaimed from a body of water, usually the sea. Canals are artificial waterways constructed to connect different water bodies (like rivers) for economic (e.g., trade) and transportation purposes.

Answer:

canals