20. What are the enzymatic mechanism using chymotrypsin model. (including close proximity and proper orientation, acid-base catalysis, covalent catalysis,
stabilization of transition state and decrease the reaction's AGE.)

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.