Most of our food comes from agriculture, so we tend to believe that it is _____ of natural biota. This is not true. In nature, _____ plants and animals _____ to the rigours of natural selection. Only the fittest survive. _____ wild populations have numerous traits for competitiveness, resistance to parasites, _____ to adverse conditions, _____ other aspects of vigour. In contrast, populations grown for many _____ under the pampered conditions of agriculture tend to lose these traits, because they _____ for production, not resilience. For example, a high-producing plant _____ lacks resistance to drought is _____ and the resistance to drought is ignored. Also, in the process of breeding plants for maximum production, all genetic variation is eliminated. (Item 6)