*Questiоns 20-21 аre bаsed оn the fоllowing: In Environmentаl Ethics, Rolston describes a case in which a non-native population of goats on San Clemente island off the California coast was threatening several plant species. The U.S. Fish and Wildlife Service decided to kill the goats, but stopped after an animal-welfare group petitioned them to use non-lethal means of removing them. The result was that many goats were removed, but not all, and to date a significant population of goats remains on the island.