Complete the sentences with the words in the box. leak, government, waves, organisation, smog, chemicals, cause, experiment

1. We\'re going to do an experiment in my science class this afternoon. 2. I believe that all this smog is caused by car fumes. 3. Chemicals from factory waste have polluted the river. 4. The factory was closed and the workers were sent home because there was a gas leak. 5. The sea was quite rough and the waves were dangerous. 6. It is essential that the government takes measures to stop the pollution of our rivers. 7. The main cause of the problem is the tons of toxic waste polluting the lake. 8. My father works for an organisation that protects marine life.