Nearly 25% of all marine life depends upon coral reefs for their survival, yet reefs make up only a very small part of the world's oceans: far less than 1% of the vast ocean floor.
(Nearly 25% of all marine life; depends; upon coral reefs; for their survival) (reefs; make up; only a very small part of the world's oceans)
Nearly 25% of all marine life reefs
depends make up
upon coral reefs for their survival
only a very small part of the world's oceans