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!
Nowadays, are primarily responsible for the disappearance of species. They are responsible for the , pollution or of species However, it should be noted that are also a cause of the disappearance of species, for example logging or of rivers.