Coral Colonies

Coral colonies live in water.They can't survive in water that is to dirty,the usually live in waters with 22c and more.But why are they important to us ?Because they control carbon dioxide in the water,they have evolved for millions of years to do this.Most of the people  think that they are just rocks that are in the oceans and the seas.But polyps live with in these coral reefs,for example the same thing is with the turtle and it's shell.Watch the video below and you will get more information on these creatures and in the video you will get a better answer on your questions about these creatures.