Except for identical twins, all the other human beings are genetically distinct from each other. why is this true?

It's because of sexual reproduction,
this causes everyone to get unique DNA patterns, (except for twins, which from by one fertilised egg splitting into 2). 50% from mum 50% from dad

When ever the sex cells go through reproduction,  our 46 cells come together to make about .01% of us, in that is everything about us, eye color, skin color, hair color, emotions. So really we all are barely different.

Wetlands form where water and land meet. a lake with a wetland fringe can fill in with decayed plant and animal material to become a wet meadow. a pond can fill in to become a bog or fen. sediment can fill in a river marsh to become a swamp.flooding of coastal lowlands from rising sea levels has created broad coastal marshes that are protected from wave action by barrier islands or reefs. coastal wetlands also form when rivers deposit sediment as they reach the ocean. plants then take root and hold the soil firm against the forces of tides and waves.