2. The kinds of whales

5. In the 17th century: fleet forms of commercial whaling

6. In the 18th and 19th centuries: whaling competition

7. In the 20th century: factory ships with whale harvesting

12. Now people in order to obtain benefits to destroy ecological

13. The three biggest commercial countries

15. The gray whales

16. The whales in Antarctic

18. No significant amount of whales recovery has take place