Answer:
Lower the emission of carbondioxide gas and planting more trees.
Explanation:
Lower the emission of carbondioxide gas and planting more trees are the two measures that have been implemented at the national level of countries to ensure the sustainability of coral reefs. Carbondioxide emission is the main reason for the destruction of coral reefs because more carbondioxide emission causes decrease the pH level of ocean. This acidic water of ocean damaged the skeleton of coral reefs and as a result thousands of organisms lost their habitat.
The Panama Canal because it makes the most money and is the most important out of all the four.
