How is a pure substance different from a mixture? a pure substances cannot be separated by physical means b mixtures cannot be separated c a pure substance is heterogeneous d a mixture is made of one substance

2positives of biotechnology: 1. plants have become more resistant to viruses and other communicable pests.2. with the of biotechnology, we have been able to produce better tasting fruits as well as vegetables.2 negatives of biotechnology: 1. biotechnology poses a number of environmental threats. genetically modifies crops often infect monarch butterflies and other insect species.2. viruses could combine with crops.