pollution/ coast of Florida/ kill/ coral reefs/ serve/ habitat/ hundreds of species of fish//

Pollution off the coast of Florida' has killed the coral reefs served as habitat for hundreds of species of fish.

Pollution off the coast of Florida has killed the coral reefs serving as habitat for hundreds of species of fish.

Pollution off the coast of Florida is killing the coral reefs, which serve as habitat for hundreds of species of fish.

Pollution off the coast of Florida killed the coral reefs serves as habitat for hundreds of species of fish.