Answer:
We need two types of environment for this experiment.
Explanation:
We need two types of environment to see the environmental effects on Caribbean reefs. In one environment we have to provide control and optimum environmental as well as biological conditions such as pH and no pollutants etc while on the other hand, we placed the Caribbean reefs in the open environment where environmental conditions are not suitable such as low pH, pollutants, algal blooms etc occurs. So we can see that the first environment have high growth rate of Caribbean reefs whereas the second environment has lower growth of Caribbean reefs due to low pH of the ocean water which prevent the growth of reef's skeleton so the conclusion of this discussion is that Caribbean reefs is negatively affected by environmental conditions.