Acompany wants to build new oceanfront housing near an estuary. the company wants to fill a saltwater marsh with dirt and cement to create more land for houses. why is this a bad idea from an ecological and commercial standpoint?

Its a bad idea, because you are taking the saltwater marsh away from the ecosystem... And turning it into a cement covered ground, for more houses... Then the animals (or other things) that live there, will die... and have to find another place to live...
 ~therefore... The bad thing is, that they shouldnt fill the marsh with dirt, and cement... Because bad things could happen to the creatures that already live there.

Answer the use of flood plains and irrigation;

Wheres the answers to the question