The correct answer is "Both authors state that coral reefs are polluting the ocean floor". That is the statement that is not true.
The rest of the statements are true:
1 - Both authors state that coral reefs are threatened.
(author 1) due to enviromental causes such us light, temperature, etc.
(author 2) little has been done to proctect them
2 - Both authors suggest that something must be done to save the reefs
(author 1) if the problem continues there will not be a suitable home for sea life
(author 2) establishing more parks would help
3 - Both authors suggest that coral reefs are fragile.
(author 1) states that the coral reefs fall apart
(author 2) says that they have a fragile enviroment