Task 1. The words in the box all appear in the passage. Fill each blank with a suitable word.

Gap-fill exercise

Fill in all the gaps, then press "Check" to check your answers. Use the "Hint" button to get a free letter if an answer is giving you trouble. You can also click on the "[?]" button to get a clue. Note that you will lose points if you ask for hints or clues!
   decreasing      endangered      extinct      interference      pollutants      protect   
1. Dinosaurs became millions of years ago.
2. She tried to herself from the wind.
3. This species of bird is in numbers every year.
4. The chemical from cars and factories make the air, water and soil dangerously dirty.
5. The blue whale is a(n) species.
6. Because of the of human beings, many animals have become extinct.