Answer: Dams can destroy the habitat's behind it. They can trap sediment and can bury rock riverbeds. This can harm the environment because fishes lives in the riverbeds being buried. River dams can flood the ecosystem which is also a bad thing.
As Dams act as Obstruction to the Natural Flow of the River, they Prevent fish from moving along the River (i.e.) either from Sea to River or From River to Sea.
The factors that affect personal health that are the most easily controlled are c) lifestyle. You can easily change the way you are living, whereas these other things cannot be.
