Hydropower requires damming a river, and many dams along rivers and creeks help prevent floods. Given these facts, hydropower requires what among the following options:
- a hydraulic system
 - increases a body's strength
 - helping to prevent floods
 - Electric generators
 - flow of electrons
 - energy of moving objects
 - power stations
 - fissures of hot, acidic water


 

   helping to prevent floods      