1. c. a contamination of natural air with dangerous gases.
2. b. a consequence of the excess dumping of toxic waste.
3. g. a contamination of both drinking water from rivers, ponds and also sea water with large amounts of human and industrial wastes.
4. f. a disturbance of silent environment with harsh loud noises.
5. a. a result of using radioactive elements from atomic energy stations.
6. d. a consequence of releasing excess heat from power plants, industries involved in metals molding, etc
7. e. a consequence of the excessive and inappropriate use of artificial light.