Baca Juga : As early as the 1940s, scientists (10. understand) that many kinds of wild animals faced extinction. Since that time, zoos (11. try) to save many endangered species, but relying on zoos to save species such as the rhinoceros is not enough. In the 1980s, the number of rhinos in the world (12. reduce) from 10,000 to 400. Many rhinos (13. kill) by poachers, but many also (14. die) in captivity. Zoo breeding programs for rhinos have not been successful. The best method of conservation (15. be) to leave them in their natural habitat. Number 12