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Complete the blanks in the text with the following words: cucumber - animals - biological - plastic - bacteria - air Life on Earth is under threat due to human activity. There is unbelievable 1) ___ waste in the oceans. Factories, power stations and vehicles pollute the 2) ___ and raise the level of carbon dioxide in the atmosphere. However, living organisms like 3) ___ that we consider responsible for infections and illnesses actually help clean up our planet! They break down waste. Without them the ground would be covered with 4) ___ waste. Scientists are even researching bacteria that can break down plastic waste! Scavengers like hyenas and vultures feed on dead 5) ___ . Without them forests and plains would be covered with dead bodies. Underwater, creatures like the sea 6) ___ work like vacuum cleaners. They help clean the sea floor and corals by removing any organic waste.
