Coral reef is the tropical rain forest of the oceans. Coral reef shows high productivity and high species diversity. Corals are coelenterate relatives of sea anemones. They are both-autotrophic and heterotrophic. The polyps catch food and also contain symbiotic unicellular dinoflagelliates.
Rain forest is any major terrestrial biome, in which trees form the dominant plants and annual rain fall is high.
Grassland is the major terrestrial biome, in which dominant plants are species of grasses, the rainfall is insufficient to support extensive growth of trees, which are also suppressed by grazing animals.
Mangroves are region of vegetation found along tropical coast, in which mangrove trees (Rhizophora species) predominate. The water logged soil is highly saline and like other halophytes mangroves are adapted to withstand these conditions. They possess aerial root called pneumatophore.