Answer:
a) It has poisoned and killed them
Explanation:
Puget Sound, located in the northwestern coast of state of Washington in the United States of America, is a body of water that used to harbor thousands of marine wildlife species.
However, through constant monitoring, scientists have shown that hundreds to thousands of marine wildlife have disappeared due to pollution, especially single-use plastic bags, which have caused the death of thousands of whales and seabirds, and the presence of toxic chemicals and eutrophication, which have caused the reduction of oxygen levels in the water, leading to the death of many fish and marine mammals.