Question

how did the mediterranean sea almost completely evaporate?
global warming
closure of the strait of gibraltar
severe drought
overuse by ancient civilizations

Explanation:

The Mediterranean Sea nearly evaporated during the Messinian Salinity Crisis, caused when tectonic activity closed the Strait of Gibraltar, cutting off the sea's main inflow of Atlantic Ocean water. Without this replenishment, high evaporation rates in the region led to the sea drying up almost entirely.

Answer:

Closure of the Strait of Gibraltar