Read the conclusion of an informative report on ocean pollution. (1) Plastic and other forms of pollution in the world’s oceans has become an urgent problem. (2) It has resulted in a rise in greenhouse gases and has contributed to climate change. (3) Plastic bags and other products threaten ocean wildlife, too. (4) Also, factory smoke can lead to dangerous air pollution. (5) To sum up, state and local governments must create new policies to prevent the spread of plastic in oceans and new programs to clean up the seas. (6) If we work together, and all do our part, we can solve this growing danger to our environment.

Which sentence should be removed to make this conclusion more effective?
Sentence 2
Sentence 3
Sentence 4
Sentence 5