Fact 1: Coral reefs provide food and shelter to many ocean organisms.

Fact 2: Coral reefs are predominantly calcite.

Given the two facts above, answer the question "What provides food and shelter to many ocean organisms?" with the following options: 
- houses
 - umbrellas
 - limestone
 - ferns
 - sharks
 - barnacles
 - calcite
 - sheds


 

       calcite  