Mangroves are the amphibians of the plant world. They straddle the land and sea, with roots that extend into salt water and house a variety of wildlife. Which choice most effectively combines the sentences at the underlined portion?
1) They straddle the land and sea, with roots that extend into salt water and house a variety of wildlife.
2) They straddle the land and sea, with roots that extend into salt water and house a variety of wildlife, making them the amphibians of the plant world.
3) They straddle the land and sea, with roots that extend into salt water and house a variety of wildlife, which makes them the amphibians of the plant world.
4) They straddle the land and sea, with roots that extend into salt water and house a variety of wildlife, therefore they are the amphibians of the plant world.