Fact 1: Corals form large colonies in shallow tropical water.

Fact 2: Water is shallow at the shore with gradual deepening.

Given the two facts above, answer the question "Where do corals form large colonies?" with the following options: 
- Mars
 - new World
 - Sediment
 - shoreline
 - environment
 - Absorb light
 - loose soil
 - polyps


 

    shoreline     