1 . A BBC film crew was working on the remote Lord Howe Island for a new wildlife documentary called Drowning in Plastic. They filmed many birds that     1     (die) for no clear reason. After some research, they found out the truth—    2     caused the death of the birds was that their stomachs were literally too full of plastic. The documentary team also filmed biologists     3     (work) on the island to save the birds. The scientists captured hundreds of chicks and removed plastic from their stomachs to give them a chance of     4     (survive).