Read the passage. Coral reefs are large, underwater formations found in the ocean that are made up of the skeletons of marine invertebrates, called coral. There are many different species of coral in oceans all over the world. Coral plays a critical role in the ocean because many species depend on coral for survival. Coral reefs help to shield coastal populations from erosion, storms, and waves. Millions of species in the ocean also depend of coral for food and shelter. But coral is in danger due to many threats including pollution and certain fishing practices. When reefs are healthy, the ocean is healthy. For this reason, many efforts have been established in order to protect coral. What does the author imply in the passage? A. Coral is commonly collected by fisherman and used for food.
B. Coral is left scarce in the ocean due to fishing practices.
C. Coral is an essential part of the ocean and should be preserved.
D. Coral is found everywhere and is in ready supply in all oceans.