Question
How does plastic trash cause marine life and sea birds to starve?
They mistake plastic for food, which clogs their stomachs and doesn't leave any room for real food.
Plastic takes up space in the water so marine animals have no place to live.
The plastic in the ocean is so dense that the marine life cannot find food easily.
Plastic doesn't cause marine life or sea bird to starve: they're smart enough to know the difference between plastic and food.
Answer
Plastic blocks access to food and takes up space in the water, making it difficult for marine life and sea birds to find food.