Approximately twenty plant species provide about 90% of the world's food. all major food crops, including corn, wheat, and soybeans, are becoming more and more genetically modified (gm) and exhibit less and less genetic variation. the crops we grow are drought tolerant and able to withstand herbicide spraying. they are more resistant to insect pests. one wild relative of corn called milpilla or  zea diploperennis, is exceptionally disease-resistant and is the only perennial in the corn family.  zea diploperennis  grows on only one mountain in western mexico. there are conflicting opinions about the use of gm crops. imagine this scenario: today we are faced with diseases we have never had to combat before; hiv-aids, ebola. imagine our agricultural corn crops are hit by a similar virulent pathogen; one that attacks members of the  zea  species. given the history of corn in the western hemisphere, what would be the best strategy for survival of the  zea  species? a) conduct research to find a way to kill the pathogen. b) decrease the gene variation in favor of more gm corn varieties. c) increase genetic variation and breed plants to contain the wild variety. d) conduct research to find a natural predator of the disease-causing pathogen.