Explanation:

Coral reefs are the most diverse of all marine ecosystems. Coral reefs are predominantly present in tropical shallow waters less than 50 meters deep. Global distribution of corals- Australia-17% Indonesia-16% Philippines-9% So, Australia, Indonesia and Philippines together host more than one-third of world’s corals. So, statement 1 and 2 are correct.

These tropical marine communities occupy less than 1% of the ocean floor, but are inhabited by at least 25% of all marine species. Scientists estimate that more than 25,000 described species from thirty-two of the world’s thirty-three animal phyla live in reef habitats – four times the number of animal phyla found in tropical rain forests. Due to this reason they are often called the rainforests of the sea. So, Statement 3 is correct.